from:"Robert ."

Hi,

Given a list, list1 having 100,000 non repeating, sorted integers ,  which of
the following methods is fastest to find an item fully understanding the item
may or may not be in the list: The binary search method which is the standard
search for such a small sample size, or the more python type statement is
 in list1?

What I am really trying to ascertain is how expensive or how efficient is  'is
 in list1'.

Thanks for your input

Robert Berman

What you don't see with your eyes, don't invent with your mouth.


___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Binary search question

Thank you all for your ideas and suggestions. The detailed explanations were
most useful.

 

Robert Berman

 

What you don't see with your eyes, don't invent with your mouth.

 

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Binary search question


> -Original Message-
> From: tutor-bounces+bermanrl=cfl.rr@python.org [mailto:tutor-
> bounces+bermanrl=cfl.rr@python.org] On Behalf Of Hugo Arts
> Sent: Friday, April 23, 2010 5:55 PM
> To: Emile van Sebille
> Cc: tutor@python.org
> Subject: Re: [Tutor] Binary search question
> 
>
>>>>>>>>>>>>>>>>>BIG SNIP   

> Of course, profiling will immediately catch that kind of performance
> bottleneck. So even if you care about performance, you can start off
> using 'in' and easily optimize later with bisect or a set, the whole
> "don't do it yet" thing and all.
> 
> Hugo

This sounds very much like the school of thought that equates optimal
efficiency with the developers level of comfort < not confidence>. So that I
might be willing to live with an occasional 7 second search time for the
general ease of using  in list. Knowing of course that eventually a
programmer who is concerned with that potential 7 second lag time will opt for
either a dictionary lookup or a bisected search.


Robert Berman

What you don't see with your eyes, don't invent with your mouth.

> ___
> Tutor maillist  -  Tutor@python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Binary search question

From: tutor-bounces+bermanrl=cfl.rr@python.org
[mailto:tutor-bounces+bermanrl=cfl.rr@python.org] On Behalf Of Ricardo
Aráoz
Sent: Friday, April 23, 2010 6:33 PM
To: Hugo Arts
Cc: tutor@python.org; Emile van Sebille
Subject: Re: [Tutor] Binary search question

Hugo Arts wrote: 
On Fri, Apr 23, 2010 at 11:33 PM, Emile van Sebille  wrote:

On 4/23/2010 2:21 PM Alan Gauld said...

"Emile van Sebille"  wrote

It's expensive enough that for a list this size I'd convert it to a
dict and use in on that. eg,

a = range(10)
d = dict(zip(a,a))

Surely that would depend on how often you do the search? If it's a one
off occurrence I'd expect the overhead of zipping and converting to a
dict would outweigh the savings?

Oh sure, but in practical terms, if it's a one-off situation who cares which
you us?  For a one-off I'd just use in and not be concerned.

I guess Alan missed my second e-mail with the micro benchmarks, but
that nuances my first answer quite a bit, and makes all the points he
is making. That does not make him less correct, of course. set (I used
frozenset, but either way) is faster than dict, and in a one-off
you're best off using bisect.

For completeness sake, on a 1 item list, using the in operator
takes *in the worst case* around 7 seconds. bisect, again in the worst
case, takes only around 0.01 seconds (that's on a Core 2 Duo T5300 @
1.7 GHZ, 2 GB RAM). That's quite a savings. those 7 seconds can easily
be 99% of the execution time of a typical script. So for sufficiently
large data set it can definitely pay off to be concerned, even with a
one-off

Of course, profiling will immediately catch that kind of performance
bottleneck. So even if you care about performance, you can start off
using 'in' and easily optimize later with bisect or a set, the whole
"don't do it yet" thing and all.

Hugo
___

In the same vein of completeness sake, and since this is the *tutor* list, we
should stress that the 'right' approach is to use 'in' whatever the case. And
only if the system is too slow and profiling shows that 'in' is the culprit
should we seek for alternatives.

Wow. I feel I have just been bh slapped across the face. I think Hugos test
results pretty much confirmed in is not the way to go although it is one of
the methods I am trying even though my tendency, since the number of elements
is always less than 1,000,000, is to use the dictionary approach. 
But, even though my years of experience using Python is less than 4 I would be
reluctant to use in just based on what I have been reading from those who
took the time to answer my post. Just my $0.02 worth.

Robert Berman

What you don't see with your eyes, don't invent with your mouth.

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Binary search question

2010-04-24 Thread Robert Berman

> -Original Message-
> From: tutor-bounces+bermanrl=cfl.rr@python.org [mailto:tutor-
> bounces+bermanrl=cfl.rr@python.org] On Behalf Of Alan Gauld
> Sent: Friday, April 23, 2010 7:41 PM
> To: tutor@python.org
> Subject: Re: [Tutor] Binary search question
> 
> "Emile van Sebille"  wrote
> 
> >BIG SNIP
> 
> And even at 1000 entries, the list creation slowed right
> down - about 10 seconds, but the searches even for "-5" were
> still around a second.
> 
> So 'in' looks pretty effective to me!
> 
> --
> Alan Gauld
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/


Now that is most impressive.


Robert Berman

What you don't see with your eyes, don't invent with your mouth.



___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

[Tutor] namespaces

2010-05-30 Thread Robert Johansson

Hi,

 

This code generates the message "UnboundLocalError: local variable 'doubles'
referenced before assignment" (line: if d[0] == d[1] and doubles == 2:)

 

http://pastebin.com/mYBaCfj1  

 

I think I have a fair picture of what it means but I would be very happy if
someone could explain the difference between the two variables h and doubles
in the code. Why is one accessible from the function but not the other? I
looked into rules for namespaces but I'm still confused. Below is another
sample of the code

 

Cheers, Robert

 

from random import *

 

h = 6

doubles = 0 # current number of consecutive doubles

 

def roll():

d = [randint(1, h), randint(1, h)]

if d[0] == d[1] and doubles == 2:

doubles = 0

return 0

elif d[0] == d[1] and doubles < 2:

doubles += 1

return sum(d)

else:

return sum(d)

 

for n in range(10):

d = roll()

print d

 

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] namespaces

2010-05-30 Thread Robert Johansson

Thanks Evert for pointing out the difference and the discussion on global 
variables, it helped. 

/Robert

-Ursprungligt meddelande-
Från: Evert Rol [mailto:evert@gmail.com] 
Skickat: den 30 maj 2010 18:34
Till: Robert Johansson
Kopia: tutor@python.org
Ämne: Re: [Tutor] namespaces

  Hi Robert

> This code generates the message "UnboundLocalError: local variable 'doubles' 
> referenced before assignment" (line: if d[0] == d[1] and doubles == 2:)
>  
> http://pastebin.com/mYBaCfj1  
>  
> I think I have a fair picture of what it means but I would be very happy if 
> someone could explain the difference between the two variables h and doubles 
> in the code. Why is one accessible from the function but not the other? I 
> looked into rules for namespaces but I'm still confused. Below is another 
> sample of the code

You assign a value to doubles in the roll() function, making Python think 
doubles is a local variable (which hasn't been assigned anything when you first 
use it, throwing the exception).
If you assign some value to h after the first line in roll() (eg, h = 6), you'd 
get the same exception, but then for h.
So, if you assign a value to a variable inside a function() and you want that 
variable to be the global one (instead of the implicitly assumed local one), 
you'll have to explicitly tell Python that: "global doubles" (probably on the 
first line in the function).
Since you hadn't assigned any value to h inside roll(), only used it, Python 
assumes it's the global one.

See also the second answer to this question: 
http://stackoverflow.com/questions/423379/global-variables-in-python

Hope that helps,

  Evert


>  
> Cheers, Robert
>  
> from random import *
>  
> h = 6
> doubles = 0 # current number of consecutive doubles
>  
> def roll():
> d = [randint(1, h), randint(1, h)]
> if d[0] == d[1] and doubles == 2:
> doubles = 0
> return 0
> elif d[0] == d[1] and doubles < 2:
> doubles += 1
> return sum(d)
> else:
> return sum(d)
>  
> for n in range(10):
> d = roll()
> print d   
>  
___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

[Tutor] random graph

2010-07-13 Thread Robert Johansson

Dear all,

 

I'm trying to check the size of a component in a random graph with this code
(by a component I mean a maximal connected sub graph):

 

http://pastebin.com/SzC77HdU

 

I'm not 100 % sure that the code is working as it should but my question is
if there is a better way to design the whole thing. 

 

Basically I start with a empty graph (just a set of nodes represented as the
numbers between 0 and 10 ** 6) and generate random edges as pairs of
integers between 0 and 10 ** 6. Also I keep a dictionary (comps) matching
nodes to component numbers. If one of the nodes of the new edge doesn't
touch an existing component, I just add that node to the dictionary and give
it the same component number as the other node. If no node touches a
component the a new component number is generated and the new nodes are
added to the dict with that number. The problem is when an edge going
between two distinct components are encountered, say that edge (n, m) is
generated going between component i and j. Now I need to change all values
for keys in one of the components to the values of the other component so
that  they merge into a single component. The way I tried to do this is to
have lists of length one as values in the dict and by that (hopefully)
manage to update all values for a whole component just by changing a single
list item (I think of them as pointers to the same list).  

 

Will this work? Is there a better way to update the values of a component
(fast)?

 

/Robert

 

 

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] has it gone quiet or is it just me?

2010-07-21 Thread Robert Berman

Same.

Robert

> -Original Message-
> From: tutor-bounces+bermanrl=cfl.rr@python.org [mailto:tutor-
> bounces+bermanrl=cfl.rr@python.org] On Behalf Of Luke
> Paireepinart
> Sent: Wednesday, July 21, 2010 2:05 PM
> To: Alan Gauld
> Cc: tutor@python.org
> Subject: Re: [Tutor] has it gone quiet or is it just me?
> 
> Not sure Alan.
> I haven't gotten any messages either, but this one came through just
> fine.
> -Luke
> 
> On Wed, Jul 21, 2010 at 12:55 PM, Alan Gauld
>  wrote:
> > I haven't had any tutor messages in 2 days.
> > Do I have a problem or are things just very quiet suddenly?
> > The archive isn't showing anything either which makes me
> suspicious.
> >
> > ___
> > Tutor maillist  -  tu...@python.org
> > To unsubscribe or change subscription options:
> > http://mail.python.org/mailman/listinfo/tutor
> >
> ___
> Tutor maillist  -  Tutor@python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] prime test problem

2010-08-21 Thread Robert Berman

Googling 'computing prime numbers' produced about 64,100,000 results . That
should certainly get you started.

 

Robert

 

From: tutor-bounces+bermanrl=cfl.rr@python.org
[mailto:tutor-bounces+bermanrl=cfl.rr@python.org] On Behalf Of Roelof
Wobben
Sent: Saturday, August 21, 2010 9:36 AM
To: tutor@python.org
Subject: [Tutor] prime test problem

 

Hello, 
 
I have to make a programm which can test if a number is a prime.
I know a prime is a number which can only be diveded by 1 and itself.
 
One way is was thinking about is to make a loop which try if % has output 0.
But that don't work.
 
Can someone give me a hint what's the best approach is.
 
Roelof
 

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] data question

2010-10-02 Thread Robert Berman



> -Original Message-
> From: tutor-bounces+bermanrl=cfl.rr@python.org [mailto:tutor-
> bounces+bermanrl=cfl.rr@python.org] On Behalf Of Roelof Wobben
> Sent: Saturday, October 02, 2010 4:35 AM
> To: tutor@python.org
> Subject: [Tutor] data question
> 
> 
> 
> Hello,
 
> Now my question is :
> 
> In which datatype can I put this data in.
> 
Perhaps a simple SQLlite database? 
http://zetcode.com/databases/sqlitetutorial/

Hope this helps,

Robert


 
> Regards,
> 
> Roelof
> 
> ___
> Tutor maillist  -  Tutor@python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Merging Text Files

2010-10-13 Thread Robert Jackiewicz

On Wed, 13 Oct 2010 14:16:21 -0600, Ara Kooser wrote:

> Hello all,
> 
>   I am working on merging two text files with fields separated by
>   commas.
> The files are in this format:
> 
> File ONE:
> *Species, Protein ID, E value, Length* Streptomyces sp. AA4,
> ZP_05482482, 2.82936001e-140, 5256, Streptomyces sp. AA4,
> ZP_05482482, 8.03332997e-138, 5256, Streptomyces sp. AA4,
> ZP_05482482, 1.08889e-124, 5256, Streptomyces sp. AA4, ZP_07281899,
> 2.92539001e-140, 5260,
> 
> File TWO:
> *Protein ID, Locus Tag, Start/Stop*
> ZP_05482482, StAA4_010100030484,
> complement(NZ_ACEV0178.1:25146..40916) ZP_07281899, SSMG_05939,
> complement(NZ_GG657746.1:6565974..6581756)
> 
> I looked around for other posts about merging text files and I have this
> program:
> one = open("final.txt",'r')
> two = open("final_gen.txt",'r')
> 
> merge = open("merged.txt",'w')
> merge.write("Species,  Locus_Tag,  E_value,  Length, Start/Stop\n")
> 
> for line in one:
>  print(line.rstrip() + two.readline().strip())
>  merge.write(str([line.rstrip() + two.readline().strip()]))
>  merge.write("\n")
> merge.close()
> 
> inc = file("merged.txt","r")
> outc = open("final_merge.txt","w")
> for line in inc:
> line = line.replace('[','')
> line = line.replace(']','')
> line = line.replace('{','')
> line = line.replace('}','')
> outc.write(line)
> 
> inc.close()
> outc.close()
> one.close()
> two.close()
> 
> This does merge the files.
> Streptomyces sp. AA4, ZP_05482482, 2.82936001e-140,
> 5256,ZP_05482482, StAA4_010100030484,
> complement(NZ_ACEV0178.1:25146..40916) Streptomyces sp. AA4,
> ZP_05482482, 8.03332997e-138, 5256,ZP_05477599,
> StAA4_01015861, NZ_ACEV0113.1:86730..102047
> 
> But file one has multiple instances of the same Protein ID such as
> ZP_05482482. So the data doesn't line up anymore.  I would like the
> program to search for each Protein ID number and write the entry from
> file 2 in each place and then move on to the next ID number.
> 
> Example of desired output:
> Streptomyces sp. AA4, ZP_05482482, StAA4_010100030484,
> 2.82936001e-140, 5256,
> complement(NZ_ACEV0178.1:25146..40916) Streptomyces sp. AA4,
> ZP_05482482, StAA4_010100030484, 8.03332997e-138, 5256,
> complement(NZ_ACEV0178.1:25146..40916)
> 
> I was thinking about writing the text files into a dictionary and then
> searching for each ID and then insert the content from file TWO into
> where the IDs match. But I am not sure how to start. Is there a more
> pythony way to go about doing this?
> 
> Thank you for your time and help.
> 
> Regards,
> Ara

Why don't you try using the csv library which is part of the standard 
python library to parse you files.  It allows simple and efficient 
manipulation of comma separated value files.

-Rob Jackiewicz

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] connect through the ip sharers

2010-10-25 Thread Robert Berman

Hi,

 

Since your post appears to be discussing a networking problem rather than a 
problem with the Python language you might have far better results posting to a 
group more attuned to network problems.

 

Good luck,

 

Robert 

 

From: tutor-bounces+bermanrl=cfl.rr@python.org 
[mailto:tutor-bounces+bermanrl=cfl.rr@python.org] On Behalf Of ???
Sent: Monday, October 25, 2010 11:54 AM
To: tutor@python.org
Subject: [Tutor] connect through the ip sharers

 

hello 

there are two computer. 

one is in here, and another is in other country.

both of two computer connected to internet by IP sharer.

I want to make program that connect both computer and send and receive data.

but my trying fails again and agian

 

it works when I try to connect each program in my computer but the other 
computer case, it fails


your little aid would be very helpful for me

thanks in advanced 

 

I've been sent similar question before but I still have no idea how to fix it 
so I submit similar question again sorry.


  _  

I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> .
SPAMfighter has removed 16 of my spam emails to date.

Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen>  
Try free scan! 
___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] connect through the ip sharers

2010-10-25 Thread Robert Berman

Hi,

 

As you well know networking opens a Pandora’s box of information so I tried 
using Google looking for ‘computer connectivity’ which has a wide range of 
topics. This may be a very good starting point you might wish to follow. The 
alternative is again using Google to look for ‘networking news groups’.

 

Also, when replying to information received by member(s) of a news group it is 
best to include the newsgroup when replying. Usually, hitting ‘reply to all’ 
will do the trick.

 

Hope this helps,

 

Robert

 

 

From: 김태윤 [mailto:kty1...@gmail.com] 
Sent: Monday, October 25, 2010 12:07 PM
To: Robert Berman
Subject: Re: [Tutor] connect through the ip sharers

 

could you tell me what group or mailing list is more attuned to network 
problems?

 

2010/10/26 Robert Berman 

Hi,

 

Since your post appears to be discussing a networking problem rather than a 
problem with the Python language you might have far better results posting to a 
group more attuned to network problems.

 

Good luck,

 

Robert 

 

From: tutor-bounces+bermanrl=cfl.rr@python.org 
[mailto:tutor-bounces+bermanrl <mailto:tutor-bounces%2Bbermanrl> 
=cfl.rr@python.org] On Behalf Of ???
Sent: Monday, October 25, 2010 11:54 AM
To: tutor@python.org
Subject: [Tutor] connect through the ip sharers

 

hello 

there are two computer. 

one is in here, and another is in other country.

both of two computer connected to internet by IP sharer.

I want to make program that connect both computer and send and receive data.

but my trying fails again and agian

 

it works when I try to connect each program in my computer but the other 
computer case, it fails


your little aid would be very helpful for me

thanks in advanced 

 

I've been sent similar question before but I still have no idea how to fix it 
so I submit similar question again sorry.

 

  _  

I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> .
SPAMfighter has removed 16 of my spam emails to date.

Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen>  
Try free scan! 

 


  _  

I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> .
SPAMfighter has removed 16 of my spam emails to date.

Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen>  
Try free scan! 
___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Summing up numbers in a file

2010-10-26 Thread Robert Berman

This certainly looks like a classroom  assignment. Please make an attempt to
solve the problem on your own. If the program fails, please copy the code you
have written and the error messages from the traceback  and someone here will
be more than happy to help you work your way through the problem.

 

Good luck,

 

Robert

 

From: tutor-bounces+bermanrl=cfl.rr@python.org
[mailto:tutor-bounces+bermanrl=cfl.rr@python.org] On Behalf Of masawudu
bature
Sent: Tuesday, October 26, 2010 4:20 PM
To: tutor@python.org
Subject: [Tutor] Summing up numbers in a file

 

How do I sum all occurrences of  a number in a file?

I have a file with a bunch of numbers, each on it's own line:

 

5
3

11
3
7
3
5
5
11
7

7

...

How do i sum them up so that the output will be ,

5 :  15

3 :   9

11:  22

7 :   21

 


  _  

I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> .
SPAMfighter has removed 16 of my spam emails to date.

Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen>
Try free scan! 
___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] if statement

2010-11-02 Thread Robert Berman



> -Original Message-
> From: tutor-bounces+bermanrl=cfl.rr@python.org [mailto:tutor-
> bounces+bermanrl=cfl.rr@python.org] On Behalf Of Glen Clark
> Sent: Tuesday, November 02, 2010 3:07 PM
> To: python mail list
> Subject: Re: [Tutor] if statement
> 
> sorry:
> 
> 
> confirmed = int(input("Are you happy with this? (y/n): ")
> 
> if confirmed == "y":
>for In in range(0,NumItems):
>   print(Entries[In] + ": " + str(In))
>change = int(input("Which item would you like to change: ")
>Entries[change]=str(input("Please enter a nem name: ")
> else:
> #do nothing

Whoops. Why are you trying to make the variable "confirmed" an integer rather
than a simple 'y/n' as you are asking for?

Robert Berman





--
I am using the free version of SPAMfighter.
We are a community of 7 million users fighting spam.
SPAMfighter has removed 34 of my spam emails to date.
Get the free SPAMfighter here: http://www.spamfighter.com/len

The Professional version does not have this message


___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Advantages or disadvantages on Platform?

2010-11-04 Thread Robert Berman



> -Original Message-
> From: tutor-bounces+bermanrl=cfl.rr@python.org [mailto:tutor-
> bounces+bermanrl=cfl.rr@python.org] On Behalf Of Jorge Biquez
> Sent: Thursday, November 04, 2010 3:44 PM
> To: tutor@python.org
> Subject: [Tutor] Advantages or disadvantages on Platform?
> 
> Hello all.
> 
> I am newbie and studying and working hard learning python. Per your
> advise I am on 2.7 . I have one question for you.
> 
> I can work on Windows (XP) or under Ubuntu .
> 
> Do you see any advantages or disadvantanges to be working in one or
> another ?

Do you see any reasons for not working in both environments?

Robert
 ___
> Tutor maillist  -  Tutor@python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor


--
I am using the free version of SPAMfighter.
We are a community of 7 million users fighting spam.
SPAMfighter has removed 34 of my spam emails to date.
Get the free SPAMfighter here: http://www.spamfighter.com/len

The Professional version does not have this message


___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] While Loops: Coin Flip Game

2010-11-14 Thread Robert Berman

From: tutor-bounces+bermanrl=cfl.rr@python.org
[mailto:tutor-bounces+bermanrl=cfl.rr@python.org] On Behalf Of Dawn Samson
Sent: Sunday, November 14, 2010 5:17 PM
To: tutor@python.org
Subject: [Tutor] While Loops: Coin Flip Game
>>>>
Greetings,

I'm a Python beginner and working my way through Michael Dawson's Python
Programming for the Absolute Beginner
import random

# set the coin
coin = random.randrange(2)
headsCount = 0
tailsCount = 0
count = 0

# the loop
while count <= 100:
    coin
    if coin == 0:
        headsCount += 1
    if coin == 1:
        tailsCount += 1
    count += 1

print "The number of heads was", heads
print "The number of tails was", tails

raw_input("\n\nPress the enter key to exit.")

Thanks,
S. Dawn Samson
>>>>>

Hi,

Think in terms of logical steps. You need to generate the results of a random
coin toss for every toss of the coin. Therefore, if you are tossing 100
tosses, you need to generate 100 results based on a probability of zero or
one.

Since this is your homework assignment you write the code, but in terms of a
logical frame work you would have something like the following.
Tossknt = 1
Generate a random toss ; results being either one or 0. Further , assume 0 is
tail; heads is one.
If toss = 1 headcount = headcount + 1
Else tailcount = tailcount + 1
Tossknt = Tossknt + 1
If Tossknt < 100 Continue loop
Else print nbr of heads tossed = , headcount
Print nbr of tails tossed = , tailcount

Obviously, this is not valid python code but it should give you enough
information to solve your problem.

Good luck,

Robert

--
I am using the free version of SPAMfighter.
We are a community of 7 million users fighting spam.
SPAMfighter has removed 53 of my spam emails to date.
Get the free SPAMfighter here: http://www.spamfighter.com/len

The Professional version does not have this message

___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

[Tutor] Help regarding lists, dictionaries and tuples

2010-11-21 Thread Robert Sjöblom

Hi. I'm new at programming and, as some others on this list, am going
through Python Programming for the Absolute Beginner. In the current
chapter (dealing with lists and dictionaries), one of the challenges
is to:
>Write a Character Creator program for a role-playing game. The player should 
>be given a pool of 30 points to spend on four attributes: Strength, Health, 
>Wisdom, and Dexterity. The >player should be able to spend points from the 
>pool on any attribute and should also be able to take points from an attribute 
>and put them back into the pool.

I don't want a direct answer on how to proceed, but a question that
arose during my thinking of the problem was whether dictionaries can
have integral data in them, like so:
attributes = {"Strength" : 28, "Health" : 12}
or if they have to be:
attributes = {"Strength" : "28", "Health" : "12"}

Ok, I'm clearly thinking in circles here. I used the interpreter to
figure out that both are fine but the first example has integers,
whereas the second has strings. Good to know. What I'm wondering then,
instead, is whether there's a good way to sum up the value of integral
data in a dictionary?

I suppose I could solve the challenge by setting up 4 different
variables and going at it that way, but since the challenge is listed
in a chapter dealing with Lists and Dictionaries (and tuples), I
figure there should be some way to solve it with those tools.

In a somewhat related note: the book gives quite hard challenges, the
coin flip challenge discussed here a few days ago, for example, comes
before the reader learns about for loops.

Thanks in advance, and best regards,
Robert S.
___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Help regarding lists, dictionaries and tuples

2010-11-21 Thread Robert Sjöblom

[Snip]
>> I don't want a direct answer on how to proceed, but a question that
>> arose during my thinking of the problem was whether dictionaries can
>> have integral data in them, like so:
>> attributes = {"Strength" : 28, "Health" : 12}
>> or if they have to be:
>> attributes = {"Strength" : "28", "Health" : "12"}
>>
>> Ok, I'm clearly thinking in circles here. I used the interpreter to
>> figure out that both are fine but the first example has integers,
>> whereas the second has strings. Good to know. What I'm wondering then,
>> instead, is whether there's a good way to sum up the value of integral
>> data in a dictionary?
>>
>
> I will point you toward two things. First, the dict class has a method
> called values(). Read the documentation on that, go into your
> interpreter, make some dictionaries, and call the values() method, see
> what comes up.
>
> The second thing is the sum() method. Again, read the documentation on
> it and experiment with it a little. Those two should suffice to answer
> your question.
They did indeed! I did run across values() before sending the message,
but didn't quite get it to work properly -- reading up on it, I
figured out that I've been calling the method completely wrong.

> I always encourage people to play around with their problems in the
> interactive interpreter, discovering what works and what doesn't for
> yourself is often a great way to learn. Combine that with
> http://docs.python.org and you've got some very powerful learning
> tools
Yeah, using the interpreter is very helpful, I've found. I find that
even if I've studied something in the documentation, I need to use the
interpreter to figure out how it actually works. Maybe that will get
better in time, but for now it's a very useful tool in
trial-and-error. I had to try out values() and sum() before I could
understand them fully.

Thanks again, much appreciated.

best regards,
Robert S.
___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Help regarding lists, dictionaries and tuples (bob gailer)

2010-11-23 Thread Robert Sjöblom

On Mon, Nov 22, 2010 at 10:27 AM,   wrote:
> Send Tutor mailing list submissions to
>        tu...@python.org
>
[snip]
>> Ok, I'm clearly thinking in circles here. I used the interpreter to
>> figure out that both are fine but the first example has integers,
>> whereas the second has strings. Good to know. What I'm wondering then,
>> instead, is whether there's a good way to sum up the value of integral
>> data in a dictionary?
>
> Why would you want to sum them? You start with 30 points in the pool,
> then allocate them to the attributes. The sum will still be 30.
> Bob Gailer

Because the user should be able to spend 30 points, or remove points
from an attribute and get them back in the pool. Like so:

attributes { "Strength" : 0, "Health" : 0, "Wisdom" : 0, "Dexterity" : 0)
points = 30 - sum(attributes.values())

Or is there a better way to achieve the same result?

best regards,
Robert S.
___
Tutor maillist  -  Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Reply All Dilemma of This List

2009-02-10 Thread Robert Berman





Mozilla Thunderbird  version 2.0.0.19 (20090105)
running under Ubuntu Linux 8.10 does not have  "Reply to Group". Even
if it did, out of habit I would be hitting the "Reply All" button. Old
preferences die hard.

Robert

spir wrote:

  Le Tue, 10 Feb 2009 12:20:51 -0500,
Brian Mathis  a écrit :

  
  
This war has been raging since the dawn of mailing lists, and you're
not likely to get a resolution now either.

  
  
Newer mail user agents have a "to list" reply button. End of war?

--
la vida e estranya
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
  



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Add readline capabilities to a Python build 2.6 on Ubuntu

2009-02-19 Thread Robert Berman

Eric,

I am running under Ubuntu 8.10. 

If I use IDLE the up arrow key gives me nothing at all. It does work
using iPython which for most testing of ideas and code snippets has
replaced IDLE.

My GUI of choice is WING-personal which costÂ  $30.00 and is by far the
best investment I have made for aÂ  very high powered python developing
environment and yes of course the open arrow works in that environment
also. 

Consider, at the least, using iPython.

Good luck,

Robert Berman

Eric Dorsey wrote:
Still doesnt work.. I just get this when I hitÂ the up
arrow:
  >>> ^[[A

  Bah. It works in the 2.5 version that came packaged with it.
Thanks for trying :)

  On Wed, Feb 18, 2009 at 11:27 PM, Ø²ÙØ§Ø¯ Ø¨Ù
Ø¹Ø¨Ø¯Ø§ÙØ¹Ø²ÙØ² Ø§ÙØ¨Ø§ØªÙÙ <ziyad.alba...@gmail.com>
wrote:
  On
Wed, 18 Feb 2009 20:19:56 -0700
Eric Dorsey <dors...@gmail.com> wrote:

> I did an aptitute install of
Â ibreadline5-dev and then
> did ./configure and make again, and still don't have any
> functionality to be able to hit up-arrow and get a command repeated
> while inside the interpreter. Any ideas?
>
>

I don't know what's wrong, Python should pickup "libreadline" and use
it automatically if it was installed.

Try passing "--with-readline" to the "configure" script.

If that doesn't help, then I'm sorry, I'm out of ideas.

Hope that help.
Ziyad.

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] String to list conversion

2009-02-24 Thread Robert Berman





Or, you could do:

In [1]: print list(raw_input('name please...'))
name please...John
['J', 'o', 'h', 'n']

Robert Berman




Kent Johnson wrote:

  On Tue, Feb 24, 2009 at 10:16 AM, Taylan Karaman
 wrote:
  
  
Hello,

I am a beginner. And I am trying to get a user input converted to a list.

print 'Enter your first name :'
firstname = raw_input()

So if the user input is

firstname = 'foo'    --->should become>
firstlist['f','o','o']

  
  
Strings behave as sequences of characters, so you can just do
firstname = 'foo'
firstlist = list(firstname)

If you just want to iterate over the letters, there is no need to
create a separate list, you can iterate over the string directly, e.g.
for letter in firstname:
  print letter

Kent
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

  



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Linear Algebra weirdness

2009-02-26 Thread Robert Berman





Hi,

I didn't get nearly as far as you.

In [2]: from LinearAlgebra import *
---
ImportError   Traceback (most recent call
last)

/home/bermanrl/ in ()

ImportError: No module named LinearAlgebra

In [3]: 

I am running Ubuntu Linux. What OS are yiou running and what version of
Python?


Robert Berman



Mr Gerard Kelly wrote:

  I am getting some very strange behaviour from the Linear Algebra module.

Look at this code:

from LinearAlgebra import *

a=5
print a

And look at the output that I get when I run it:

50.0
0.0
0.25
0.0
0.5
0.0
0.75
0.0
1.0
[[  2.5000e-01  -2.5000e-01  -4.3750e-01 ...,
3.73459082e+01   3.75116710e+01   3.76764961e+01]
 [  5.e-01  -5.e-01  -6.2500e-06 ...,
   -4.3797e-01  -2.49373966e-03   4.3766e-01]
 [  7.5000e-01  -7.5000e-01   0.e+00 ...,
   -7.5000e-01   0.e+00   7.5000e-01]
 [  1.e+00  -1.e+00   0.e+00 ...,
   -1.e+00   0.e+00   1.e+00]]
5


Apparently Linear Algebra is giving me the output of another program along with the output for this one. Of course I don't need Linear Algebra to print the number 5, but I've been trying to make a program that uses Linear Algebra, and I'm always having the output come out twice each time I run it. When I edit the program, it always gives me the old output before the new output, even if I edit it right down to something as simple as "a=5, print a".

Is anybody familiar with this module and why it is doing this? I've used it before and never had this issue.

-Gerard.
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

  



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

[Tutor] Gtk time control and Glade

2009-03-17 Thread Robert Berman

I am writing a Blood-Glucose Analysis application for Diabetics. I am 
using Python 2.5 under Ubuntu 8.10 and Glade 3.4.5.


Manually recorded test results require a calendar control for the date 
of the test (no problem) and a timer control for the time of the 
test(big problem). While Glade certainly supports a calender control 
with a great deal of documentation, there is not an available time 
control for Glade. Nor was I able to find a general time control for 
Gtk. I did find one for wxwidgets but I am not using wxwidgets nor am I 
using PyQt.


I am reasonably sure such a control exists. I know I'm not the only 
individual who needs date and time controls. But, using Google has 
provided all kinds of information, there has not been a specific 
statement about any specific controls. At this time I do not feel I have 
the level of expertise to build my own control and it is something I 
would rather not have to do.


Have any of you heard of such an available time control specifically for 
Gtk and available or capable of being used by Glade.


Thank you for any insights and suggestions.


Robert Berman
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Gtk time control and Glade

2009-03-17 Thread Robert Berman


Thank you Chris, that will certainly get me started.

Robert

Chris Fuller wrote:
Make your own.  You can have empty containers in glade that you fill in at 
runtime, or you could create the interface in glade, perhaps a couple of 
ComboBoxes.  I would leave an empty container and create a reusable widget 
descended from gtk.HBox that implements validation or anything else that it 
would need to do.  Maybe it could default to the current time, for instance.


I know its possible to configure glade to use custom widgets, but I've never 
bothered to learn about since it's so easy (and free of caveats that I might 
become subject to) to leave empty space for runtime use.


Here's a quick and dirty (and untested!) example:

class TimeEntry(gtk.HBox):
def __init__(self):
gtk.HBox.__init__(self)

self.hr = \
w = gtk.ComboBox()

for i in range(24):
w.append_text('%02d'%(i,))

self.pack_start(w, False, False, 0)
w.show()

w = gtk.Label(':')
self.pack_start(w, False, False, 0)
w.show()

self.min = \
w = gtk.ComboBox()

for i in range(60):
w.append_text('%02d'%(i,))

self.pack_start(w, False, False, 0)
w.show()

def get(self):
return '%02d:%02d' % (self.hr.get_active(),self.min.get_active())

Cheers

On Tuesday 17 March 2009 09:25, Robert Berman wrote:
  

I am writing a Blood-Glucose Analysis application for Diabetics. I am
using Python 2.5 under Ubuntu 8.10 and Glade 3.4.5.

Manually recorded test results require a calendar control for the date
of the test (no problem) and a timer control for the time of the
test(big problem). While Glade certainly supports a calender control
with a great deal of documentation, there is not an available time
control for Glade. Nor was I able to find a general time control for
Gtk. I did find one for wxwidgets but I am not using wxwidgets nor am I
using PyQt.

I am reasonably sure such a control exists. I know I'm not the only
individual who needs date and time controls. But, using Google has
provided all kinds of information, there has not been a specific
statement about any specific controls. At this time I do not feel I have
the level of expertise to build my own control and it is something I
would rather not have to do.

Have any of you heard of such an available time control specifically for
Gtk and available or capable of being used by Glade.

Thank you for any insights and suggestions.


Robert Berman
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor


___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

  

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Executing a C Program from RH Linux in Python for Win

2009-03-18 Thread Robert Berman


Wayne,

I think I do the opposite of what you are doing. I develop in Python on 
a Linux (Ubuntu 8.10) box. On that box, I also run a virtual copy of 
Windows XP in its own little happy environment. That way, when my XP 
customers have a problem, I drop into the desktop environment running XP 
and we are off and running.


From the gist of your comment, you want to run Linux from within your 
Windows OS? Well, given the miracle of Virtual Memory, you can do that. 
Download the Xvm Virtual Memory (free) package from Sun and install it 
on your Windows system. Then, allocate a Linux system under the auspices 
of VM and you are off and running.


Hope this is of some help.

Robert Berman


Wayne Watson wrote:
The Subject contains the interest here. Can it be done? I think it 
this case it requires executing the program command line with 
parameters then executing it? How dependent upon the C compiled code 
is this? That is, I would think various distributions of Linux might 
produce different executable code. The too I would want to do this in 
Win. Is there, in fact, some Linux environment in Win that would allow 
me to test its executable?

--
   Wayne Watson (Watson Adventures, Prop., Nevada City, CA)

 (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time)


“Life is one damn thing after another."
 -- Mark Twain 
  



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
  

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Posting to Tkinter NG in new.gmane.org

2009-03-26 Thread Robert Berman

Is this a news group or a list group. If it is a news group, you can't 
use your regular email. I use T-Bird and to subscribe to 'news groups' 
you must have access to a news group server. If you look under the news 
properties under servers, you must provide a news group server (NNTP). 
Your email server(usually POP) will not work.


Robert Berman

Alan Gauld wrote:


"Wayne Watson"  wrote



   My e-mail address is valid. Any ideas? I've compacted related 
Trash folders, etc



 It should be news.gmane.org... Or is that just a typo?


In that case you probably need to tell us more.
Can you read the group OK in TBird?

What other settings are you using?
I can't help much as I don't use TBird...

Alan G

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor


___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

[Tutor] PDF to text conversion


Hi,

I must convert a history file in PDF format that goes from May of 1988 
to current date.  Readings are taken twice weekly and consist of the 
date taken mm/dd/yy and the results appearing as a 10 character numeric 
+ special characters sequence. This is obviously an easy setup for a 
very small database  application with the date as the key, the result 
string as the data.


My problem is converting the PDF file into a text file which I can then 
read and process. I do not see any free python libraries having this 
capacity. I did see a PDFPILOT program for Windows but this application 
is being developed on Linux and should also run on Windows; so I do not 
want to incorporate a Windows only application.


I do not think i am breaking any new frontiers with this application. 
Have any of you worked with such a library, or do you know of one or two 
I can download and work with? Hopefully, they have reasonable 
documentation.


My development environment is:

Python
Linux
Ubuntu version 8.10


Thanks for any help  you might be able to offer.


Robert Berman
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] PDF to text conversion


Bob,

Thank you for the quick reply. I am acquainted with that method, and 
that will certainly work to do some really serious testing; but, the 
data collection is an ongoing process and  the users are requesting that 
every month the latest entries (8) are brought into the system. What is 
rather irksome is that the output from the system cannot be changed from 
PDF to text; so obviously I am going to have to resolve the situation at 
my end.


I am envisioning a simple program that once started reads the data file, 
converts the data into text, and then sends the data to the database. 
The program doesn't care if there are 8 test results or 80,000 test 
results. That is why i am looking for a python module.


Thanks again,

Robert Berman

bob gailer wrote:

Robert Berman wrote:

Hi,

I must convert a history file in PDF format that goes from May of 
1988 to current date.  Readings are taken twice weekly and consist of 
the date taken mm/dd/yy and the results appearing as a 10 character 
numeric + special characters sequence. This is obviously an easy 
setup for a very small database  application with the date as the 
key, the result string as the data.


My problem is converting the PDF file into a text file which I can 
then read and process. I do not see any free python libraries having 
this capacity. I did see a PDFPILOT program for Windows but this 
application is being developed on Linux and should also run on 
Windows; so I do not want to incorporate a Windows only application.


I do not think i am breaking any new frontiers with this application. 
Have any of you worked with such a library, or do you know of one or 
two I can download and work with? Hopefully, they have reasonable 
documentation.


If this is a one-time conversion just use the save as text feature of 
adobe reader.




My development environment is:

Python
Linux
Ubuntu version 8.10


Thanks for any help  you might be able to offer.


Robert Berman
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor





___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] PDF to text conversion

Hello Emad,

I have seriously looked at the documentation associated with pyPDF. This
seems to have the page as its smallest element of work, and what i need
is a line by line process to go from .PDF format to Text. I don't think
pyPDF will meet my needs but thank you for bringing it to my attention.

Thanks,

Robert Berman

Emad Nawfal (عماد نوفل) wrote:

On Tue, Apr 21, 2009 at 12:54 PM, bob gailer <mailto:bgai...@gmail.com>> wrote:

Robert Berman wrote:

Hi,

I must convert a history file in PDF format that goes from May
of 1988 to current date. Readings are taken twice weekly and
consist of the date taken mm/dd/yy and the results appearing
as a 10 character numeric + special characters sequence. This
is obviously an easy setup for a very small database
application with the date as the key, the result string as
the data.

My problem is converting the PDF file into a text file which I
can then read and process. I do not see any free python
libraries having this capacity. I did see a PDFPILOT program
for Windows but this application is being developed on Linux
and should also run on Windows; so I do not want to
incorporate a Windows only application.

I do not think i am breaking any new frontiers with this
application. Have any of you worked with such a library, or do
you know of one or two I can download and work with?
Hopefully, they have reasonable documentation.

If this is a one-time conversion just use the save as text feature
of adobe reader.

My development environment is:

Python
Linux
Ubuntu version 8.10

Thanks for any help you might be able to offer.

Robert Berman
___
Tutor maillist - Tutor@python.org <mailto:Tutor@python.org>
http://mail.python.org/mailman/listinfo/tutor

--
Bob Gailer

Chapel Hill NC
919-636-4239

___
Tutor maillist - Tutor@python.org <mailto:Tutor@python.org>
http://mail.python.org/mailman/listinfo/tutor

I tried pyPdf once, just for fun, and it was nice:
http://pybrary.net/pyPdf/
--
لا أعرف مظلوما تواطأ الناس علي هضمه ولا زهدوا في إنصافه
كالحقيقة.محمد الغزالي

"No victim has ever been more repressed and alienated than the truth"

Emad Soliman Nawfal
Indiana University, Bloomington

___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] PDF to text conversion

First, thanks to everyone who contributed to this thread. I have a 
number of possible solutions and a number of paths to pursue to 
determine which avenue I should take to resolve this remaining issue. I 
did try the itools library and while everything installed nicely, most 
of the tests failed so I am not particularly overjoyed with the results.


Thank you Dinesh for the vote of sympathy. I do appreciate it.

I did use Adobe Reader to convert the history PDF file into a text file 
and it did seem to do it faithfully. So now I will work out a parsing 
function to extract my data and send it to a SQLLITE database.


I am thrilled both with the number of suggestions I have received from 
this group and the quality of the suggestions.


Thanks again,

Robert Berman





Norman Khine wrote:

the itools library from hforge.org has a PDF2TEXT implementation itools.pdf

http://www.hforge.org/itools

norman

On Tue, Apr 21, 2009 at 8:44 PM, Dayo Adewunmi  wrote:
  

Emile van Sebille wrote:


Robert Berman wrote:


  

Have any of you worked with such a library, or do you know of one or two
I can download and work with? Hopefully, they have reasonable documentation.

My development environment is:

Python
Linux
Ubuntu version 8.10



I've used

[r...@fcfw2 /]# /usr/bin/pdftotext -v
pdftotext version 2.01
Copyright 1996-2002 Glyph & Cog, LLC
[r...@fcfw2 /]# cat /etc/issue
Red Hat Linux release 9 (Shrike)


HTH,

Emile

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

  

Hi Robert,
pdftotext is part of poppler-utils, an Ubuntu package which can be installed
like so:

sudo aptitude install poppler-utils

But I to would be interested in finding a python library/module for this.

Regards,

Dayo
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

  

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] PDF to text conversion

2009-04-22 Thread Robert Berman


Dinesh,

I have pdftotext version 3.0.0.  I have decided to use this to go from 
PDF to text. It is not the ideal solution, but is is a certainly doable 
solution.


Thank you,

Robert

Dinesh B Vadhia wrote:
The best converter so far is pdftotext from 
http://www.glyphandcog.com/ who maintain an open source project at 
http://www.foolabs.com/xpdf/.
 
It's not a Python library but you can call pdftotext from with Python 
using os.system().  I used the pdftotext -layout option and that gave 
the best result.  hth.
 
dinesh
 


Message: 4
Date: Tue, 21 Apr 2009 18:37:39 -0400
From: Robert Berman mailto:berma...@cfl.rr.com>>
Subject: Re: [Tutor] PDF to text conversion
To: tutor@python.org <mailto:tutor@python.org>
Message-ID: <49ee4ab3.4040...@cfl.rr.com 
<mailto:49ee4ab3.4040...@cfl.rr.com>>

Content-Type: text/plain; charset=ISO-8859-1; format=flowed

First, thanks to everyone who contributed to this thread. I have a
number of possible solutions and a number of paths to pursue to
determine which avenue I should take to resolve this remaining issue. I
did try the itools library and while everything installed nicely, most
of the tests failed so I am not particularly overjoyed with the results.

Thank you Dinesh for the vote of sympathy. I do appreciate it.

I did use Adobe Reader to convert the history PDF file into a text file
and it did seem to do it faithfully. So now I will work out a parsing
function to extract my data and send it to a SQLLITE database.

I am thrilled both with the number of suggestions I have received from
this group and the quality of the suggestions.

Thanks again,

Robert Berman



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
  

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Number cruncher

2009-04-22 Thread Robert Berman


Hello John,

It is the general policy of the 'tutors group' to not solve homework 
problems. Given that very basic rule, there are obvious elements for 
which we can definitely give help. But, you have to take the first step 
and that is a relatively big one. You have to define an algorithm or 
recipe to solve the problem. To do so, you must define your inputs. As a 
first comment, while you did specify that each assignment is weighted, 
you gave no indication that a grade was a required input. Obviously a 
heavily weighted '88' may carry more import than a very light weight '94'.


What you need to do is define (1) Your inputs, (2) your outputs (what 
comes out of the recipe and how you want it served. ie, how displayed. 
And then, once you have defined the obvious you must resolve the heart 
of the algorithm, how do you compute the outputs.


Hopefully, while this is certainly not 'the' answer it will get you started.

Robert Berman

John Jenkinson wrote:
I need to write code that determines a students final grade based on 
the number of each type of assignment turned in with its corresponding 
weighted percentage.  There will be 15-20 inputs.  I have not reached 
this point in my learning of python, so I would like to request a 
resource that would help me for this project.
 
- John Jenkinson



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
  

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Python help

2009-04-22 Thread Robert Berman


Yes.

Show us your solution and perhaps we can help you make it a tad more 
efficient.


Robert Berman

IT_ForMe wrote:

Anyone know how to program this using Python

Add up the prices for items in a shopping cart. Some items are taxable and
some items are not. You may assume a 7% tax rate for all taxable items.
Apply a 10% discount if the customer is a student. (hint, instead of asking
the user to input items, set them up as an associative array in the code)
  

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Lists in a file

2009-04-26 Thread Robert Berman


David,

You are processing a text file. It is your job to treat it as a file 
comprised of lists. I think what you are saying is that each line in the 
text file is a list. In that case


for line in fileobject:
   listline = list(line)

Now, listline is a list of the text items in line.

Hope this helps.

Robert Berman

David Holland wrote:

Hi,

I am trying to create a program where I open a file full of lists and 
process them.

However when the program does not recognize the lists as lists.
Here is the relevant code :-
def open_filedef():
text_file =open ("voteinp.txt","r")
lines = text_file.readlines()
   
   
for line in lines:

print line
print line[0]
 
text_file.close()


And an example of the type of text :-

['a','b','c']
['e','d','f']

Any ideas?


Thanks in advance


David Holland




___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
  

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

[Tutor] Different Command Result Executing in Shell vs. Program

2009-05-09 Thread robert mcquirt


  
  
  
  
  
  
   
  
 
  
   Hi. I've not been working with Python very long and have run into a puzzling 
thing. I'm working on a program that needs to identify the filetype of files 
without extensions. Using the file command in the shell works fantastic, as in:
   
   
rob...@ubuntu:~$ file -b linuxlogotag
   JPEG image data, JFIF standard 1.01
   
   
I want to be able to perform the same task in a program for batch processing. 
After a bit of research, I found that I can execute the shell command from 
within a Python program using:
   
   
import os
   os.system('file -b /home/robert/linuxlogotag')
   
   
This also works fine. The problem is that when I try to replace the hard coded 
path/name with a string variable for looping, the results are not the same as 
the shell's. Here's the modified code I'm using for testing (the original code 
is from Bogdan's blog at http://bogdan.org.ua/).
   
   
import os, glob
   path = '/home/robert'
   for infile in glob.glob( os.path.join(path, '*.*') ):
 testCommand = "'file -b " + infile + "'"
 print testCommand,
 test = os.system(testCommand)
 print test
   
   
The code does indeed step through all the files in the directory and the 
testCommand string constructs properly. Yet, the output is not the same as 
shell results. All files, regardless of type, simply output the number 32512, 
with no description.

   
   I have searched forums, read the man file and perused several Python 
references and have not been able to find the answer. Why does the same command 
yield different results, depending on how it's run? Any education is greatly 
appreciated.

   
   Linux 2.6 (kubuntu 8.04)
   Python 2.5.2
   file command 4.21
  


  ___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Different Command Result Executing in Shell vs. Program

2009-05-10 Thread robert mcquirt

@alan: Thank you very much for the information you provided and also for 
suggesting your tutorial. I am now studying the subprocess module. I was 
impressed with the depth of your tutorial and am studying it as well (and not 
just for my current problem). Thanks again.

@dave: Thanks for your reply Dave. I did try removing the quote as you 
suggested and then received an error of missing quote. As best I can determine 
the quotes are needed to surround the command being used in the os.system() 
context. However, your reply did serve to remind me to check the simple 
possibilities first before seeking a more involved solution. Thanks again for 
that.  



  ___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

[Tutor] Iterating over list of functions

Hi,

Given a list of options: option_1...option_n. For each option I have
a corresponding function: func_1. func_n. I have all function names
defined in a list similar to flist = [func_1, func_2,...func_n]
which I know is a legitimate construct having found a similar  construct
discussed by Kent Johnson in 2005.

What I do not know how to do is to call the selected function. If the
index of options is 1, then I want to call func_2; do I code
flist[index]? I do not think Python has a branch indirect construct so I
cannot use anything similar to that methodology.  What is the best
approach to take to solve this problem?

Thank you for any assistance, hints, solutions, and guidelines.

Robert




___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Iterating over list of functions

Thank you, Emile.

That is the exact answer I needed.

Robert


On Wed, 2009-05-20 at 07:48 -0700, Emile van Sebille wrote:

> On 5/20/2009 7:25 AM Robert Berman said...
> > Hi,
> > 
> > Given a list of options: option_1...option_n. For each option I have
> > a corresponding function: func_1. func_n. I have all function names
> > defined in a list similar to flist = [func_1, func_2,...func_n]
> > which I know is a legitimate construct having found a similar  construct
> > discussed by Kent Johnson in 2005.
> > 
> > What I do not know how to do is to call the selected function. If the
> > index of options is 1, then I want to call func_2; do I code
> > flist[index]?
> 
> Yes - with trailing () of course...
> 
> def func1():return 1
> def func2():return 2
> def func3():return 3
> flist = [func1,func2,func3]
> flist[0]()
> flist[1]()
> flist[2]()
> 
> Emile
> 
> 
>   I do not think Python has a branch indirect construct so I
> > cannot use anything similar to that methodology.  What is the best
> > approach to take to solve this problem?
> > 
> > Thank you for any assistance, hints, solutions, and guidelines.
> > 
> > Robert
> > 
> > 
> > 
> > 
> > ___
> > Tutor maillist  -  Tutor@python.org
> > http://mail.python.org/mailman/listinfo/tutor
> > 
> 
> ___
> Tutor maillist  -  Tutor@python.org
> http://mail.python.org/mailman/listinfo/tutor
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Iterating over list of functions

Thank you, Christian. This solution was one I was not expecting and am
glad to receive it. It is one I will explore in greater detail later.

Robert


On Wed, 2009-05-20 at 16:44 +0200, Christian Witts wrote:
> Robert Berman wrote:
> > Hi,
> >
> > Given a list of options: option_1...option_n. For each option I have
> > a corresponding function: func_1. func_n. I have all function names
> > defined in a list similar to flist = [func_1, func_2,...func_n]
> > which I know is a legitimate construct having found a similar  construct
> > discussed by Kent Johnson in 2005.
> >
> > What I do not know how to do is to call the selected function. If the
> > index of options is 1, then I want to call func_2; do I code
> > flist[index]? I do not think Python has a branch indirect construct so I
> > cannot use anything similar to that methodology.  What is the best
> > approach to take to solve this problem?
> >
> > Thank you for any assistance, hints, solutions, and guidelines.
> >
> > Robert
> >
> >
> >
> >
> > ___
> > Tutor maillist  -  Tutor@python.org
> > http://mail.python.org/mailman/listinfo/tutor
> >
> >   
> Why not use a dictionary to do the heavy lifting for you
> 
>  >>> import string
>  >>> funcs = {1:string.upper, 2:string.lower}
>  >>> funcs[1]('this is a simple test')
> 'THIS IS A SIMPLE TEST'
>  >>> funcs[2]('THIS IS A SIMPLE TEST')
> 'this is a simple test'
> 

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

[Tutor] Iterating through a function list

Hi,

Given a list of options: option_1...option_n. For each option I have
a corresponding function: func_1. func_n. I have all function names
defined in a list similar to flist = [func_1, func_2,...func_n]
which I know is a legitimate construct having found a similar  construct
discussed by Kent Johnson in 2005.

What I do not know how to do is to call the selected function. If the
index of options is 1, then I want to call func_2; do I code
flist[index]? I do not think Python has a branch indirect construct so I
cannot use anything similar to that methodology.  What is the best
approach to take to solve this problem?

Thank you for any assistance, hints, solutions, and guidelines.

Robert

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Iterating over list of functions

Alan,

The emphasis of your reply certainly makes me look at the dictionary
solution as the most 'correct' solution to utilize. Before I change the
code I just implemented, let me make sure I understand exactly what you
are saying and what you are advocating. The 'dictionary of functions' is
the 'best' approach because of simplicity and because it minimizes
chances or errors. The one area you did not address is the area of
efficiency. Is this method also the most efficient solution?

The reason I am trying to pin you are two fold. First, you are a
powerful spokesman for 'correct and proper' coding in the Python
community and I take  your opinions and commentaries seriously. Again,
how efficient is this method and is it truly the 'most pythonesque'
oriented code.

Thanks again,

Robert

On Wed, 2009-05-20 at 16:07 +0100, Alan Gauld wrote:

> "Robert Berman"  wrote
> 
> > Thank you, Christian. This solution was one I was not expecting and am
> > glad to receive it. It is one I will explore in greater detail later.
> 
> A dictionary of functions is the most common way to tackle 
> this fairly common requirement. It combines readability with 
> ease of maintenance, there is no chance of using the wrong 
> index.
> 
> >> Why not use a dictionary to do the heavy lifting for you
> >> 
> >>  >>> import string
> >>  >>> funcs = {1:string.upper, 2:string.lower}
> >>  >>> funcs[1]('this is a simple test')
> >> 'THIS IS A SIMPLE TEST'
> >>  >>> funcs[2]('THIS IS A SIMPLE TEST')
> >> 'this is a simple test'
> 
> 
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Need help solving this problem

2009-06-10 Thread Robert Berman

What you are looking at is a simulation whereby a coin having 2 outcomes
(heads or tails) is flipped exactly 100 times. You need to tell how many
times the coin falls heads up and how many times the coin falls tails
up. 

First become familiar with the random module. Assign a value of 1 for
heads and a value of 2 for tails. Then you are going to use a structure
of the random module which will return only two possible outcomes.
Either a one or a two. You are going to loop (look at range(1,101) or
range(0,100). (Side question; why 101 or 0 to 100?; look closely at the
meaning of the range arguments). Simply count the number of ones and the
number of two's in the 100 flips then print the results. 

Good luck.

Robert

On Wed, 2009-06-10 at 13:08 -0700, Raj Medhekar wrote:
> I have been teaching myself Python using a book. The chapter I am on
> currently, covers branching, while loops and program planning. I am
> stuck on on of the challenges at the end of this chapter, and I was
> hoping to get some help with this. Here it is:
> 
> Write a program that flips a coin 100 times and the tells you the
> number of heads and tails.
> 
> I have tried to think about several ways to go about doing this but I
> have hit a wall. Even though I understand the general concept of
> branching and looping, I have been having trouble writing a program
> with these.  I look forward to your reply that will help me understand
> these structures better.
> 
> Sincerely,
> Raj
> 
> 
> 
> 
> ___
> Tutor maillist  -  Tutor@python.org
> http://mail.python.org/mailman/listinfo/tutor
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

[Tutor] How do I do this in python?

2009-06-11 Thread Robert Lummis

I want to write a function that I can use for debugging purposes that
prints the values of whatever list of object references it is given as
arguments, without knowing in advance how many object references it
will be called with or what they might be. For example, the call:
show(a,b,c) would output the values of the arguments like this:

a = 3
b = 'john'
c = 'Monday'

while show (x) would output (for example):

x = 3.14

of course displaying whatever the actual current values are. For a
collection object it would make sense to output just the first few
values.

So within the 'show' function definition I have to somehow get a list
of the literal argument names it was called with and then use the
names as globals to get the values. How do I do that?

If this can't be done but there is a completely different way to
achieve a similar result, what is it?

I'm trying to learn python but it's a struggle because the
documentation is so dispersed. If there is a solution to this
question, what documentation could I have looked at to find it on my
own?

BTW I'm using python 3.01 if it matters.

-- 
Robert Lummis
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] How do I do this in python?

2009-06-11 Thread Robert Lummis

On Thu, Jun 11, 2009 at 11:58 AM, spir wrote:
> Le Thu, 11 Jun 2009 10:46:26 -0400,
> Kent Johnson  s'exprima ainsi:
>
>> On Wed, Jun 10, 2009 at 9:43 PM, Robert Lummis
>> wrote:
>> > I want to write a function that I can use for debugging purposes that
>> > prints the values of whatever list of object references it is given as
>> > arguments, without knowing in advance how many object references it
>> > will be called with or what they might be. For example, the call:
>> > show(a,b,c) would output the values of the arguments like this:
>> >
>> >    a = 3
>> >    b = 'john'
>> >    c = 'Monday'
>> >
>> > while show (x) would output (for example):
>> >
>> >    x = 3.14
>>
>> Here is a pretty clean solution. It passes names rather than values,
>> then looks the values up in the caller's stack frame. Written for
>> Python 2.x but should work for 3.x if you change the prints.
>>
>> In [1]: import sys
>> In [11]: def show(names):
>>    :     frame = sys._getframe(1)
>>    :     for name in names.split():
>>    :         if name in frame.f_locals:
>>    :             print name, '=', frame.f_locals[name]
>>    :         else:
>>    :             print name, 'not found'
>>
> [...]
>>
>> Kent
>
> Waow, great!
>
> Denis
> --
> la vita e estrany
> ___
> Tutor maillist  -  tu...@python.org
> http://mail.python.org/mailman/listinfo/tutor
>

Thanks for all the intelligent and thoughtful replies to my newB
question. It looks like this tutor mailing list is going to be a big
help!  It's going to take me some time and trial and error to digest
all the replies so I understand them fully but it will be instructive.

I guess one thing I learned already, even though I didn't ask about
it, is that using python3 isn't the best way to start out.

Again, thank you all for taking the time to reply.
-- 
Robert Lummis
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] Help Needed

2009-06-16 Thread Robert Berman

You are putting far too much work into the solution. Look up slicing on
the python web page. Then, as an example,


In [1]: s1 = 'hello world'

In [2]: s1[::-1]
Out[2]: 'dlrow olleh'

Hope this helps,

Robert

On Tue, 2009-06-16 at 14:25 -0700, Raj Medhekar wrote:
> I had previously emailed y'all regarding inverting a message input by
> the user of the program backwards. After much contemplation on your
> earlier replies I came up with the code I have included in this email.
> The problem I am having with this code is that the the first character
> of the message that is reversed does not come up. Is there a solution
> to this? For my message that I input I used "take this" to test it,
> use the same message when the program prompts you to enter the message
> and run it, you'll see what I mean. Also is there a way to say reverse
> the string in a way so the reversed string would result to "this take"
> if you use my example? And is there a way to stop the loop without the
> use of break? Thanks for the help!
> 
> Peace,
> Raj
> 
> My Code:
> 
> # Backward message
> # program gets message from user then prints it out backwards
> 
> message = raw_input("Enter your message: ")
> 
> print message
> 
> high = len(message)
> low = -len(message)
> 
> begin=None
> while begin != "":
> begin = int(high)
> 
> if begin:
> end = int(low)
> 
> print "Your message backwards is",
> print message[begin:end:-1]
> break
> 
> 
> raw_input("\n\nPress the enter key to exit")
> 
> 
> 
> 
> 
> 
> 
> 
> ___
> Tutor maillist  -  Tutor@python.org
> http://mail.python.org/mailman/listinfo/tutor
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

[Tutor] List Splicing

Greetings,

I am working on a 'simple' algorithm to solve the problem called PRIME1
explained at http://www.spoj.pl/problems/PRIME1/. 

I do have an algorithm based on the Sieve of Eratosthenes and it does
work as I am failing the project not because of a computational error
but because of the dreaded TLE (time limit exceeded) designator. I have
determined there are at least 3 areas for improvement. The first is
within my code where I am creating a list of the first million primes. 
The code is as follows:

def BuildSieve(itemsin):
TheSieve=list()
TheSieve = range(0,itemsin+1)
TheSieve[1]=0
for i in range(2,itemsin+1):
if (TheSieve[i] > 0):
j = i + i
while (j <= itemsin):
TheSieve[j] = 0
j+=i
return TheSieve

It is called with PrimaryList = BuildSieve(100)

I have read that list splicing rather than looping to set a range of
items to zero is the best approach. Given an example  list  of

In [53]: l1
Out[53]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

Since 3 is a prime, we can eliminate all multiples of 3. Within l1,
these are expressed as

In [52]: l1[n+n:len(l1):n]
Out[52]: [6, 9, 12]

when n = 3. ( do know 12 would have been eliminated by the prime number
2)

It would be great if I could say l1[n+n:len(l1):n] = 0 but obviously
that will fail for obvious reasons. I am looking for the right hand side
of the statement to set a list within the list to all zeros. Also, if
anyone had a relatively simple explanation why in Python this is faster
than a loop, I would really like to understand it.

Thanks for the input.

Robert



___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] List Splicing

Emile,

Thank your for your comments. I do have a list running from 0-101.
Yes, it is true, I only needed 0 - 10 and yes I will change it.
However, if you use primearray as a sieve of all primes 2-100 you
will see it works quite well. Printing a range, say primearray[21]
through primearray[50] will give you all prime numbers between 21 and
50.

23
29
31
37
41
43
47

73000 to 99,123 works nicely, too. I did, in the beginning use a list of
100 (actually (101) and that worked well so thank you for corroborating
the approach.

Another question I will ask after this one is resolved involves the
methodology I use to find primes well over one million.

However, for the time being, can you perhaps share some suggestions on
list splicing?

Thank you for your assistance.

Robert

On Wed, 2009-06-17 at 15:25 -0700, Emile van Sebille wrote:
> On 6/17/2009 3:03 PM Robert Berman said...
> > Greetings,
> > 
> > I am working on a 'simple' algorithm to solve the problem called PRIME1
> > explained at http://www.spoj.pl/problems/PRIME1/. 
> > 
> > I do have an algorithm based on the Sieve of Eratosthenes and it does
> > work as I am failing the project not because of a computational error
> > but because of the dreaded TLE (time limit exceeded) designator. I have
> > determined there are at least 3 areas for improvement. The first is
> > within my code where I am creating a list of the first million primes. 
> 
> It looks more like it creates a list 101 in length where the 
> non-zero numbers in that list are primes.  I'd try BuildSieve(100) until 
> BuildSieve was returning just primes.
> 
> Or, are you trying to create a list of the primes under 100?
> 
> Optimization should proceed once you've got it working.
> 
> Emie
> 
> ___
> Tutor maillist  -  Tutor@python.org
> http://mail.python.org/mailman/listinfo/tutor

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] List Splicing

Emille,

Thank you for the example of list splicing.  Do you know if this is
faster than a more conventional loop statement as in my code for
primearray which is in my original post (reprinted here)

The code is as follows:

def BuildSieve(itemsin):
TheSieve=list()
TheSieve = range(0,itemsin+1)
TheSieve[1]=0
for i in range(2,itemsin+1):
if (TheSieve[i] > 0):
j = i + i
while (j <= itemsin):
TheSieve[j] = 0
j+=i
return TheSieve

It is called with PrimaryList = BuildSieve(100)

Again, thank you for your help.

Robert


On Wed, 2009-06-17 at 17:01 -0700, Emile van Sebille wrote:

> On 6/17/2009 4:48 PM Robert Berman said...
> > Emile,
> > 
> > Thank your for your comments. I do have a list running from 0-101.
> > Yes, it is true, I only needed 0 - 10 and yes I will change it.
> > However, if you use primearray 
> 
> you haven't posted the primearray code...
> 
> 
> > 
> > However, for the time being, can you perhaps share some suggestions on
> > list splicing?
> 
> So, this part of your original post--
>  > Out[53]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
>  >
>  > Since 3 is a prime, we can eliminate all multiples of 3. Within l1,
>  > these are expressed as
>  >
>  > In [52]: l1[n+n:len(l1):n]
>  > Out[52]: [6, 9, 12]
>  >
>  > when n = 3. ( do know 12 would have been eliminated by the prime
>  > number 2)
>  >
>  > It would be great if I could say l1[n+n:len(l1):n] = 0
> 
> but you can say:
> 
> for ii in l1[n+n:len(l1):n]: l1[ii] = 0
> 
> Is something like that what you're after?
> 
> Emile
> 
> 
> 
>  > but obviously
>  >
>  > that will fail for obvious reasons. I am looking for the right hand
>  > side of the statement to set a list within the list to all zeros.
> ---
> 
> ___
> Tutor maillist  -  Tutor@python.org
> http://mail.python.org/mailman/listinfo/tutor
___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] List Splicing

Wayne,

Thank you for the suggestion. I will let you know how well this plays
out.

Robert




On Wed, 2009-06-17 at 19:26 -0500, Wayne wrote:
> On Wed, Jun 17, 2009 at 7:11 PM, Robert Berman 
> wrote:
> Emille,
> 
> Thank you for the example of list splicing.  Do you know if
> this is  faster than a more conventional loop statement as in
> my code for primearray which is in my original post (reprinted
> here)
> 
> 
> The code is as follows:
> 
> def BuildSieve(itemsin):
> TheSieve=list()
> TheSieve = range(0,itemsin+1)
> TheSieve[1]=0
> for i in range(2,itemsin+1):
> if (TheSieve[i] > 0):
> j = i + i
> while (j <= itemsin):
> TheSieve[j] = 0
> j+=i
> return TheSieve
> 
> It is called with PrimaryList = BuildSieve(100)
> 
> 
> I'm curious if it wouldn't be faster to use xrange. I know for certain
> instead of range(0, itemsin+1) you could use TheSieve = [1, 2]
> TheSieve.extend(range(3, itemsin+1,2))
> 
> Which would save you at least half the time in your generation. Since
> your first step should be removing multiples of two, that should be a
> big help.
> 
> HTH,
> Wayne
> 
> 

___
Tutor maillist  -  Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor

Re: [Tutor] List Splicing