Re: [Tutor] Tutor Digest, Vol 50, Issue 43
>
> Message: 1
> Date: Mon, 14 Apr 2008 01:31:41 -0700
> From: "Dinesh B Vadhia" <[EMAIL PROTECTED]>
> Subject: [Tutor] encode unicode strings from pysqlite
> To:
> Message-ID: <[EMAIL PROTECTED]>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Here is a program that SELECT's from a pysqlite database table and encode's
> the returned unicode strings:
>
> import sys
> import os
> import sqlite3
>
> con = sqlite3.connect("testDB.db")
> cur = con.cursor()
>
> a = u'99 Cycling Swords'
> b = a.encode('utf-8')
> print b
>
> q = '%wor%'
> limit = 25
> query = "SELECT fieldB FROM testDB WHERE fieldB LIKE '%s' LIMIT '%s'" %(q,
> limit)
> for row in cur.execute(query):
> r = str(row)
> print r.encode('utf-8')
Why not change this to:
> for row in cur.execute(query):
> for item in row:
> print item.encode('utf-8')
which will return a string ?
Kinuthia.
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Re: [Tutor] Tutor Digest, Vol 50, Issue 56
> > -- > > Message: 3 > Date: Thu, 17 Apr 2008 10:58:00 -0700 > From: Dick Moores <[EMAIL PROTECTED]> > Subject: Re: [Tutor] python assignments > To: Python Tutor List > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > At 04:42 AM 4/17/2008, you wrote: > >Dear friends, > > > >I covered few introductory books on python. B4 going for an advanced > >book, i want to take up small, small assignments and try to solve > >with python. Can someone please suggest me any url where i can have > >assignments and solutions. > > http://projecteuler.net/index.php?section=problems Hi, this link is not loading. > > Dick Moores > ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Executing from Python prompt
Hi, I do not know what I am doing wrong. When I run the following code from the Python prompt it executes without a murmur. But when I save it as a .py file and try to execute it from the shell, it just returns the prompt...actually it is all scripts that return a value which are behaving in this manner. def factorial(n): if n <= 1: return 1 else: return n * factorial(n-1) factorial(some number here) The same happens when I use IDLE. Thanks! Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Executing from Python prompt
On Sat, 2008-04-19 at 16:06 -0400, bob gailer wrote: > kinuthia muchane wrote: > > Hi, > > > > I do not know what I am doing wrong. When I run the following code from > > the Python prompt it executes without a murmur. But when I save it as > > a .py file and try to execute it from the shell, it just returns the > > prompt...actually it is all scripts that return a value which are > > behaving in this manner. > > > > > > def factorial(n): > > if n <= 1: > > return 1 > > else: > > return n * factorial(n-1) > > > > factorial(some number here) > > > > > print factorial(some number here) > > When you enter an expression at the interactive prompt you see the > value. Not true when you run a program. Expression values must be > printed. So you are doing nothing wrong. Thanks, Bob, it worked the first time. It was staring me in the face the whole time! Thanks once again. Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tutor Digest, Vol 50, Issue 63
> "kinuthia muchane" <[EMAIL PROTECTED]> wrote > > > I do not know what I am doing wrong. When I run the following code > > from > > the Python prompt it executes without a murmur. But when I save it > > as > > a .py file and try to execute it from the shell, it just returns the > > prompt...actually it is all scripts that return a value which are > > behaving in this manner. > > The >>> prompt evaluates expressions and prionts the value. > The interpreter on the other hand does not automatically print > values you ghave to explicitly tell it to print using the print > statement. > > So in your case just add the print command in front of the > function call and all will be well. > > > factorial(some number here) > > print factorial(n) > > HTH, > > > -- > Alan Gauld Thanks, that worked. Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Computing factorial...
Hi,
I wanted to calculate the factorial of a given number without using
recursion. I came up with the following code, although it is not very
elegant it works.
def factorial(*args):
product = args[0]
for item in args[1:]:
product *= item
return product
number = int(raw_input('Enter value of number to compute factorial '))
seq = range(1,number + 1)
if number <= 0:
print -1
else:
print factorial(*seq)
When I change that code a bit to (In fact, this is what I started with,
it almost drove me crazy trying to figure out what was wrong!) :
def factorial(*args):
temp = args[0]
for item in args[1:]:
product = temp * item
return product
number = int(raw_input('Enter value of number to compute factorial '))
seq = range(1,number + 1)
if number <= 0:
print -1
else:
print factorial(*seq)
... it just echoes back the number you were prompted to enter.
My confusion is, aren't the variables 'temp' and 'product' storing the
same value ie "args[0]". So why would they return different values, the
one with "temp" giving a wrong answer?
Thanks!
Kinuthia...
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[Tutor] Project Euler Problem 6
Hi, I am trying to solve problem 6 on the Project Euler, but when I submit my answer, I am told that it is wrong. Here is the problem: The sum of the squares of the first ten natural numbers is, 1² + 2² + ... + 10² = 385 The square of the sum of the first ten natural numbers is, (1 + 2 + ... + 10)² = 55² = 3025 Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 − 385 = 2640. Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum. And here is my code: def aux(): return sum([k*k for k in range(1,111)])# sum of the squares of the first one hundred numbers def aux1(): inter = sum([k for k in range(1,111))# square of the sum of the first one hundred numbers return inter**2 def aux2(): return aux1() - aux()# the difference of the two sums print aux2() ...which gives a result of 36821290. It worked fine with the example they have given but not with the hundred one... What am I missing? Thanks! Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Euler Problem 6
Hi, I think I need to be more careful in the future. This line return sum([k*k for k in range(1,111)]) should be: return sum([k*k for k in range(1,101)]). ... and this one sum([k for k in range(1,101)) also changes to: sum([k for k in range(1,101)) Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Else Clause In A Loop
Hi,
I learnt that a loop can have an else clause. And that this clause
executes when the loop TERMINATES. In a while loop when the condition
becomes false, and in a for loop when a sequence is exhausted. When I
write the following code it seems to work:
for n in [1,2,3,4,5]:
print 'we are in the loop',n
else:
print 'we are now EXITING the loop',n
which results in:
we are in the loop 1
we are in the loop 2
we are in the loop 3
we are in the loop 4
we are in the loop 5
we are now EXITING the loop 5
Or:
n = 1
while n <= 5:
print 'we are in the loop',n
n += 1
else:
print 'we are now EXITING the loop',n
...which gives:
we are in the loop 1
we are in the loop 2
we are in the loop 3
we are in the loop 4
we are in the loop 5
we are now EXITING the loop 6 (it spills over here!)
This has served to confuse me more. Would someone please kindly explain
how all this fits into the code below which searches (and finds!) for
prime numbers...
def prime():
number = int(raw_input("Enter a number :"))
for i in range(2,number):
for j in range(2,i):
if i%j == 0:
break
else:
print "is a prime number", i
prime()
...especially in the instance when number is 2 in the first for
statement, for then we will have for j range(2,2)! Or what is going
on??
Thanks,
Kinuthia...
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Re: [Tutor] Else Clause In A Loop
On Mon, 2008-05-12 at 14:08 -0400, "Simón A. Ruiz" wrote:
> I'll try my hand at this:
>
> The outside for loop is looking through every number up to the variable
> "number".
No quarrel here.
>
> For each of those numbers, it checks to see if any number between 2 and
> i is divisible into i. If it finds anything, we know it's not a prime,
> and so it breaks out of that second loop without completing it, which
> means the else block isn't executed.
This is where I am getting lost. When the variable 'number' is 3, it
means that in that instance the inner 'for' statement will be 'for j in
range(2,3)', hmmm which means that we will be dividing each element by 2
in the first 'for' statement and checking whether it is true , no? But
2%2 is zero, so, in my warped logic, the inner 'for' loop should break
and the else clause will not execute!
>
> If it can't find anything that i is divisible by, then that inside for
> loop finishes without breaking, we know that i is a prime number, and
> the "else" clause is executed.
This is where it gets even more interesting for me. Wont 'i' in one
instance be 8, so at that particular moment there will be a 7 in the
inner 'for' loop which will be divisible by one of our 'prime' numbers
ie 7?! I know I am wrong but for some reason I cannot see the light! :-)
>
> range(2,2) is is an empty list, so the loops ends uneventfully without
> doing anything and the else clause is executed.
>
> I'm not an expert, and this seems to me to be what's happening there.
>
> Simón
All the same, thanks...
>
> kinuthia muchane wrote:
> > Hi,
> >
> > I learnt that a loop can have an else clause. And that this clause
> > executes when the loop TERMINATES. In a while loop when the condition
> > becomes false, and in a for loop when a sequence is exhausted. When I
> > write the following code it seems to work:
> >
> > for n in [1,2,3,4,5]:
> > print 'we are in the loop',n
> > else:
> > print 'we are now EXITING the loop',n
> >
> > which results in:
> >
> > we are in the loop 1
> > we are in the loop 2
> > we are in the loop 3
> > we are in the loop 4
> > we are in the loop 5
> > we are now EXITING the loop 5
> >
> > Or:
> >
> > n = 1
> > while n <= 5:
> > print 'we are in the loop',n
> > n += 1
> > else:
> > print 'we are now EXITING the loop',n
> >
> > ...which gives:
> >
> > we are in the loop 1
> > we are in the loop 2
> > we are in the loop 3
> > we are in the loop 4
> > we are in the loop 5
> > we are now EXITING the loop 6 (it spills over here!)
> >
> > This has served to confuse me more. Would someone please kindly explain
> > how all this fits into the code below which searches (and finds!) for
> > prime numbers...
> >
> >
> > def prime():
> >number = int(raw_input("Enter a number :"))
> >for i in range(2,number):
> > for j in range(2,i):
> > if i%j == 0:
> > break
> > else:
> > print i, "is a prime number"
> > prime()
> >
> > ...especially in the instance when number is 2 in the first for
> > statement, for then we will have for j in range(2,2)! Or what is going
> > on??
> >
> > Thanks,
> > Kinuthia...
> >
> >
> > ___
> > Tutor maillist - Tutor@python.org
> > http://mail.python.org/mailman/listinfo/tutor
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Re: [Tutor] Else Clause In A Loop
On Tue, 2008-05-13 at 11:09 -0400, "Simón A. Ruiz" wrote: > kinuthia muchane wrote: > > On Mon, 2008-05-12 at 14:08 -0400, "Simón A. Ruiz" wrote: > >> For each of those numbers, it checks to see if any number between 2 and > >> i is divisible into i. If it finds anything, we know it's not a prime, > >> and so it breaks out of that second loop without completing it, which > >> means the else block isn't executed. > > > > This is where I am getting lost. When the variable 'number' is 3, it > > means that in that instance the inner 'for' statement will be 'for j in > > range(2,3)', hmmm which means that we will be dividing each element by 2 > > in the first 'for' statement and checking whether it is true , no? But > > 2%2 is zero, so, in my warped logic, the inner 'for' loop should break > > and the else clause will not execute! > > When i is 3, then we'll only check (2 % 3 == 0) which is False, so the > loop ends unbroken and runs the else clause letting us know that 3 is > indeed a prime number. Shouldn't we be checking for (3%2 == 0) instead of (2%3 == 0)? > > Never will we check (2 % 2 == 0). > > When i is 2, range(2,2) returns [], so the loop ends unbroken (without > starting) and runs the else clause. > > >> If it can't find anything that i is divisible by, then that inside for > >> loop finishes without breaking, we know that i is a prime number, and > >> the "else" clause is executed. > > > > This is where it gets even more interesting for me. Wont 'i' in one > > instance be 8, so at that particular moment there will be a 7 in the > > inner 'for' loop which will be divisible by one of our 'prime' numbers > > ie 7?! I know I am wrong but for some reason I cannot see the light! :-) > > Don't worry about it, you're doing fine. > > Remember, when you're most confused you're most ready to learn > something. :-D > > Ok, so when i is 8, we check: > is (8 % 2 == 0)? True. Break! > So, we've broken out of the inner loop and thus ignore the else > statement. We know 8 is not a prime number. > > Now, for a prime. When i is 7, we check: > is (7 % 2 == 0)? False. Next! > is (7 % 3 == 0)? False. Next! > is (7 % 4 == 0)? False. Next! > is (7 % 5 == 0)? False. Next! > is (7 % 6 == 0)? False. Next! > So, we've finished the inner loop without breaking, so we now run the > else clause: > is a prime number 7 > > > Does this help at all? It was crystal clear! Thanks Simon (I didn't know how to put the accent mark over the 'o', though), the confusion is gone. ;) > > Hope this finds you all having a beautiful day! > > Simón ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] String Replacement Question
st = "String" print "%s " %st*3 String String String Does this help? Kinuthia... - Message: 6 Date: Wed, 21 May 2008 15:05:21 +0530 From: Faheem <[EMAIL PROTECTED]> Subject: [Tutor] String Replacement question To: tutor@python.org Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset=US-ASCII Hi all, How do I replace the same value multiple times without repeating the same variable name/value repeatedly? for ex. some = 'thing' print '%s %s %s %s' % (some,some,some,some) in this case, my question is how do i replace "% (some,some,some)" with something more concise? thanks in advance, Faheem ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] String Replacement Question
Moishy Gluck wrote: >>> "%s " %st*3 'String String String ' ^ If you look closely at the end of the string there is an extra space. >>> " ".join((st, )*3) 'String String String' ^ No extra space. Ah...Okay! On Wed, May 21, 2008 at 9:42 AM, Kinuthia Muchane <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote: st = "String" print "%s " %st*3 String String String Does this help? Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tutor Digest, Vol 51, Issue 51
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Today's Topics:
1. Re: Equivalent 'case' statement (Alan Gauld)
2. Re: Equivalent 'case' statement (inhahe)
3. Reading only a few specific lines of a file (Jason Conner)
4. Re: Reading only a few specific lines of a file (John Fouhy)
5. Re: String Replacement question (Faheem)
--
Message: 1
Date: Fri, 23 May 2008 00:25:23 +0100
From: "Alan Gauld" <[EMAIL PROTECTED]>
Subject: Re: [Tutor] Equivalent 'case' statement
To: tutor@python.org
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
"Dinesh B Vadhia" <[EMAIL PROTECTED]> wrote
Is there an equivalent to the C/C++ 'case' (or 'switch') statement
in Python?
No, just if/elif
However you can often achieve similar results with a dictionary:
def func1(v): return v
def func2(v): return v*2
switch = { 'val1': func1, # use a function for each value
'val2': func2,
'val3': lambda v: "this is three!" } # or use
lambda if preferred
val = raw_input("Value? (val1,val2,val3)")
Something small here. This
print switch.[val](val)
should be: print switch[val](val)
### which is equivalent to:
if val == 'val1': print func1(val)
elif val == 'val2': print func2(val)
elif val == 'val3': print "this is three"
HTH,
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Re: [Tutor] Equivalent 'case' Statement
Hi,
I messed in earlier message, my apologies.
Message: 1
Date: Fri, 23 May 2008 00:25:23 +0100
From: "Alan Gauld" <[EMAIL PROTECTED]>
Subject: Re: [Tutor] Equivalent 'case' statement
To: tutor@python.org
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
"Dinesh B Vadhia" <[EMAIL PROTECTED]> wrote
Is there an equivalent to the C/C++ 'case' (or 'switch') statement
in Python?
No, just if/elif
However you can often achieve similar results with a dictionary:
def func1(v): return v
def func2(v): return v*2
switch = { 'val1': func1, # use a function for each value
'val2': func2,
'val3': lambda v: "this is three!" } # or use
lambda if preferred
val = raw_input("Value? (val1,val2,val3)")
This:
print switch.[val](val)
should be: print switch[val](val)
### which is equivalent to:
if val == 'val1': print func1(val)
elif val == 'val2': print func2(val)
elif val == 'val3': print "this is three"
HTH,
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Re: [Tutor] RegEx to search for the '$' symbol
> --
>
> Message: 4
> Date: Wed, 11 Jun 2008 10:35:30 +0100 (GMT+01:00)
> From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Subject: [Tutor] RegEx to search for the '$' symbol
> To: tutor@python.org
> Message-ID: <[EMAIL PROTECTED]>
> Content-Type: text/plain;charset="UTF-8"
>
> Hi,
> Silly question but how do you use python's re module to find
> dictionary items that contain the '$' symbol.
Hi,
I no expert but here is my dime's worth...
> >>> import re
> >>> d = {'k':'$',1:'2','p':'$','j':'$dollar','l': 'dol$lar'}
> >>> for i in d.values():
> ... re.findall(r'.*\$.*',i)
> ...
>
> []
> ['$']
> ['$dollar']
> ['dol$lar']
> []
>
> NB:
> Empty matches are included in the result unless they touch the beginning of
> another match.
>
>
>
Kinuthia...
> Thanks
> David
>
>
>
>
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[Tutor] Two dimesional array
On Thu, 2008-06-19 at 02:30 +0200, [EMAIL PROTECTED] wrote: > Message: 2 > Date: Wed, 18 Jun 2008 19:43:21 +0530 > From: "amit sethi" <[EMAIL PROTECTED]> > Subject: [Tutor] (no subject) > To: tutor@python.org > Message-ID: > <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="iso-8859-1" > > Hi , Could you please tell me , how i can traverse a two dimensional >>> from numpy import * # import the necessary module > >>> arry = array((1,2,3,4)) # create a rank-one array > >>> print arry > [1 2 3 4] > >>> print arry.shape > (4,) # this means it is a rank 1 array with a length of 4 (the trailing > comma means it is a tuple) > > To get to the first element in the array: > print arry[0] > 1 > > To get to the last element: > >>> print arry[-1] > 4 > >>> > > >>> arry2 = array(([5,6,7,8],[9,10,11,12])) # create a a rank-two array, > >>> two-dimensional, if wish > >>> print arry2 > [[ 5 6 7 8] > [ 9 10 11 12]] > >>> print arry2.shape # > (2, 4) # this means that it is a rank 2 (ie 2-dimensional) array, with each > axis having a length of 4 > >>> > To get to the first element in the first axis: > >>> print arry2[0,0] > 5 > To get to the last element in the second axis: > >>> print arry2[1,-1] > 12 > > Does this help? > Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tutor Digest, Vol 52, Issue 66
On Tue, 2008-06-24 at 15:26 +0200, [EMAIL PROTECTED] wrote: > Message: 5 > Date: Tue, 24 Jun 2008 05:47:29 -0700 (PDT) > From: Danny Laya <[EMAIL PROTECTED]> > Subject: [Tutor] fibonacci.py task ??? > To: tutor@python.org > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="iso-8859-1" > > Hi all, can you explain me what this code mean : > > Fibonacci.py > > # This program calculates the Fibonacci sequence > a = 0 > b = 1 > count = 0 > max_count = 20 > while count < max_count: > count = count + 1 > # we need to keep track of a since we change it > old_a = a > old_b = b > a = old_b > b = old_a + old_b > # Notice that the , at the end of a print statement keeps it > # from switching to a new line > print old_a, > > > Output: > > 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 > > Do you understand it ??? Can you explain meahhh you know > i'm a newbie so please explain it with a simple expalanation. > > And I got many tutorial with title *.py(e.g: Fibonacci.py and > Password.py), > can you explain me what *.py mean? Thank's for helping me. > If you have an algorithm to calculate the sum of exactly two(!) numbers you could do it in the Python prompt by: >>> 3+4 7 ... or you could start you fire up a text editor (something like Notepad in Windows, or nano in Linux and type "3+4"(without the quotes!), hmmm..., and save the file as anything you want, lets say for now you save the file as "threePlusFour". Every time you invoke the python interpreter (do you know how to do that?) with "threePlusFour", you will get the value seven! Because there are many programming languages, such as C, java, perl, ruby, haskell(!), you might want to be more specific as to what programming language you save saved your code in. .c for C, .rb for Ruby, .java for java and, of course .py for python. ... or you could define a function... One of the indefatigable contributors to this mailing list, Alan Gauld (where do you get the time?), has an excellent tutorial for beginners. Check it out at http://www.freenetpages.co.uk/hp/alan.gauld (correct?) Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tutor Digest, Vol 52, Issue 69
On Wed, 2008-06-25 at 01:49 +0200, [EMAIL PROTECTED] wrote: > > ... or you could start you fire up a text editor (something like > > Notepad > > in Windows, or nano in Linux and type "3+4"(without the quotes!), > > Actually it would need to be > > print 3+4 > > otherwise Python would silently evaluate the expression but > not display the result. Oh my, I was in the middle of something, something like http://projecteuler.net/index.php?section=problems&id=74 > > > One of the indefatigable contributors to this mailing list, Alan > > Gauld > > (where do you get the time?), > > With increasing difficulty! :-) I can understand that. > > > Check it out at http://www.freenetpages.co.uk/hp/alan.gauld > > (correct?) > > Correct, thanks for the plug! > > Sadly it will need to move soon since Freenet have > announced that they will soon be decommissioning > their free web site(*). I'm trying to decide whether to go to > another free site or spend the money for a proper > hosted site with dedicated domain name etc... Here (in Kenya) the cheapest unlimited internet access option costs you around 9600 Kenya Shillings, about $146 a month! I am already stumped! > > (*) They have already blocked ftp so I can't post updates > anymore :-( Dommage, dommage... > ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Invoking Python
On Tue, 2008-06-24 at 11:11 -0700, Danny Laya wrote: > ... or you could start you fire up a text editor (something like > Notepad > in Windows, or nano in Linux and type "3+4"(without the quotes!), > hmmm..., and save the file as anything you want, lets say for now you > save the file as "threePlusFour". Every time you invoke the python > interpreter (do you know how to do that?) with "threePlusFour", you > will > get the value seven! > > Well HE..HE i don't know. Let say I write the "threePlusFour" file in > /home/danny/threePlusFour.py > How I can invoke that file > ??? >From the forward slashes in the file path I assume you are using a Linux based >OS, Ubuntu perhaps? Well, to use python you need to to start the terminal or the shell. In Ubuntu, go to Main Menu ==> Accessories and click on Terminal, you will now have a new window open with something like this --- [EMAIL PROTECTED]:~$ . Enter the name "python" followed by the name of your file. In this case you should enter "python /home/danny/threePlusFour.py"(without the quotes!). If you want to enter into the Python interactive prompt, simply type python and you should be rewarded with something like: Python 2.5.1 (r251:54863, Oct 5 2007, 13:36:32) [GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> The ">>>" there means python is waiting for you to enter commands. Try 3+4, or 4/3 Does this help? Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Invoking Python
On Thu, 2008-06-26 at 12:00 +0200, [EMAIL PROTECTED] wrote: > Or more commonly add a first line like: > > #! /path/to/python/executable > > Then you can simply make the file executable and run it by typing its > name > > $ threeplusfour.py On my computer, running Linux Ubuntu, I always have to type ./threePlusFour.py to get it to run. Otherwise I get a not found command. > > or double clicking it in your favourite file manager GUI tool. > > See the topic "Add a Little style" in my tutorial, in the box > Note for Unix users > for more details. > ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Invoking Python
On Thu, 2008-06-26 at 09:57 -0400, bhaaluu wrote:
> You can create a Python script on a *nix system and run it with:
>
> $ python threeplusfour.py
>
> You can place a shebang line as the first line of the script, which points
> to the python interpreter:
>
> #!/usr/bin/python
> print("Hello, world!\n")
>
> Save the file, then make it an executable with:
>
> $ chmod u+x threeplusfour.py
>
> Then execute it with:
>
> $ ./threeplusfour.py
>
> Why the dot-slash? Here is a good explanation:
> http://www.linfo.org/dot_slash.html
>
> You can also create a Python script and place it in a directory that is
> included in your PATH (echo $PATH). Once the executable script is in
> a directory in your PATH, you can execute it with:
>
> $ threeplusfour.py
bhaluu, I was not having a problem with any of that, it was Danny
Laya! :-)
>
> Happy Programming!
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Re: [Tutor] Tutor Digest, Vol 52, Issue 87
On Sun, 2008-06-29 at 10:20 +0200, [EMAIL PROTECTED] wrote: > Message: 1 > Date: Sat, 28 Jun 2008 21:53:44 -0400 > From: Kirk Z Bailey <[EMAIL PROTECTED]> > Subject: [Tutor] arrays in python > To: tutor@python.org > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Just wondering, if I can find a way to do a 2 dimensional array in > python. 1 dimension would be a list it would seem; for 2, I could use > a > list of lists? > > Strange how I can't think of ever needing one since I discovered > snake > charming, but so many languages do foo dimensional arrays, it would > seem > like there ought to be a way to do it in python. > > -- >>> from numpy import * # import the necessary module >>> arry = array((1,2,3,4)) # create a rank-one array >>> print arry [1 2 3 4] >>> print arry.shape (4,) # this means it is a rank 1 array with a length of 4 (the trailing comma means it is a tuple) To get to the first element in the array: >>> print arry[0] 1 To get to the last element: >>> print arry[-1] 4 >>> arry2 = array(([5,6,7,8],[9,10,11,12])) # create a a rank-two array, two-dimensional, if wish >>> print arry2 [[ 5 6 7 8] [ 9 10 11 12]] >>> print arry2.shape # > (2, 4) # this means that it is a rank 2 (ie 2-dimensional) array, with each axis having a length of 4 >>> To get to the first element in the first axis: >>> print arry2[0,0] 5 To get to the last element in the second axis: print arry2[1,-1] 12 You can slice it, reshape it, literally you can contort in way you want! Does this help? Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Problem Euler 26
Hi, I am trying to solve Problem Number 26 (http://projecteuler.net/index.php?section=problems&id=26) on project Euler but apparently the answer I am submitting is wrong. Here is the problem: A unit fraction contains 1 in the numerator. The decimal representation of the unit fractions with denominators 2 to 10 are given: 1/2 = 0.5 1/3 = 0.(3) 1/4 = 0.25 1/5 = 0.2 1/6 = 0.1(6) 1/7 = 0.(142857) 1/8 = 0.125 1/9 = 0.(1) 1/10 = 0.1 Where 0.1(6) means 0.16..., and has a 1-digit recurring cycle. It can be seen that 1/7 has a 6-digit recurring cycle. Find the value of d < 1000 for which 1/d contains the longest recurring cycle in its decimal fraction part. I am giving the answer 38, because 1/38 = 0.0263157894. It seems I have misunderstood the question or I cant solve it! Here is the code that I came up with: def aux(num): import re pattern = re.compile(r"^0?1?2?3?4?5?6?7?8?9?$") frac ="%.9f"%(1.0/num) fracSlice = frac[2:]# get the decimal fractional part, ie remove '0.' fracList = list(fracSlice) #convert string to a list fracList.sort() # I need to sort , because I will be searching by increasing order testFrac = "".join(fracList) # convert list back to a string, phew! if re.match(pattern,testFrac): # if the pattern matches, the number is our candidate print (num,fracSlice) for b in xrange(1,1000): aux(b) Er... er, that does not exactly work as expected but it narrows the search to only 3 candidates because of the inclusion of the zero: (28, '035714286') (38, '026315789') (81, '012345679') For 28, the digit, in the fractional part, after 8 is 5, so 5 is repeated and as for, 81 the next digit after 7 is 0, so again 0 occurs twice. But for 38, the next digit after 9 is 4, and because it has NOT occurred before, I assume 38 is the correct answer... and I am wrong! I suspect I have completely misunderstood the question. Any ideas? Thanks! Kinuthia... ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tutor Digest, Vol 53, Issue 18
On Sat, 2008-07-05 at 20:23 +0200, [EMAIL PROTECTED] wrote: > Message: 7 > Date: Sat, 05 Jul 2008 12:23:36 -0600 > From: Nathan Farrar <[EMAIL PROTECTED]> > Subject: [Tutor] Exploring the Standard Library > To: Python Tutor > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="us-ascii" > > I'd like to spend some time exploring the standard library. I'm > running > python on Ubuntu. How would I find the location of the modules > (find / > -name "os.py" does not yield results)? In Ubuntu, you can find all the documentation in the /usr/share/doc directory. Therefore, for python you will find it in /usr/share/doc/python. Furthermore, to find the location of some documentation, in the terminal enter dpkg -L , in your case, just type dpkg -L python and you will be rewarded with paths for all python related documentation. Does this help? Kinuthia... > > Thanks! > Nathan ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Newbie
On Fri, 2008-07-25 at 03:47 +0200, [EMAIL PROTECTED] wrote:
> Message: 9
> Date: Thu, 24 Jul 2008 18:47:32 -0700 (PDT)
> From: Sam Last Name <[EMAIL PROTECTED]>
> Subject: [Tutor] Newbie
> To: tutor@python.org
> Message-ID: <[EMAIL PROTECTED]>
> Content-Type: text/plain; charset="us-ascii"
>
> mmmkay its me again
> Iv'e been learning alot and have found so much joy in making programs
> that solve equations using the input function.
> I need Help on this though.
> Im trying to make a program where it solves the quadratic formula when
> you put in the variables.
> Here wats i got so far. :) and also, is there a function for square
> root?
>
> a = input("What is the variable a?")
> b = input("What is the variable b?")
> c = input("What is the variable c?")
> # this is where i need help :(
> print -b + /sqrt (b*b - 4*a*c)/(2*a)
> # this of course doesn't work i believe because i don't have the
> square root function and don know how to make one
>>> import math
>>> print math.sqrt(6)
2.44948974278
>>> print math.sqrt(8)
2.82842712475
>>>
math is a module which contains most of the mathematical functions that
you need most of the time. Here we used just one of them, sqrt, to find
the square root of an integer. The Python Library Reference lists all of
them and their usage.
Does this help?
Kinuthia...
>
> Feedback appreciated :)
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Re: [Tutor] Tutor Digest, Vol 53, Issue 99
On Tue, 2008-07-29 at 01:12 +0200, [EMAIL PROTECTED] wrote:
> Message: 3
> Date: Mon, 28 Jul 2008 13:26:13 -0500
> From: "Daniel Sarmiento" <[EMAIL PROTECTED]>
> Subject: Re: [Tutor] Memory error - how to manage large data sets?
> To: tutor@python.org
> Message-ID:
> <[EMAIL PROTECTED]>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi
>
> I tried to run your code and checked (with top) the memory ussage and
> it uses more than 2 Gb of memory.
>
> I tried to modify the code a little bit to use less memory and came up
> with this:
>
> fib = {0:0,1:1}
> even = []
>
> def fibonacci(x,y):
>return x+y
>
> for j in xrange (2,100):
> i = fib[j-1] + fib[j-2]
> if i % 2 == 0:
> even.append(i)
> fib = {j-1:fib[j-1], j:i}
>
> total = reduce(fibonacci,even)
> print total
>
> First, I replaced range with xrange.
> I figured that you only need the last two values in the fibonnaci
> series to calculate the next value, so I replaced the fib list with a
> dictionary to only store the last two values instead of the whole
> series.
>
> It looks like the progam still hangs and I did not notice any memory
> imrovements when running it with 1 000 000
>
> Am I wrong thinking that the modifications I made help use less
> memory?
>
I have realised that when you need to work with large numbers, lists are
slow and tend to gobble up bytes. Another thing try to be as simple as
possible :). This is how I would approach the problem, without using
lists. It produces the result instantly, even for large numbers like a
100, 000, 000.
def fibonacci()
a = 0
b = 1
evenTotal = 0
while a < 1:
a,b = b,a+b
if a%2 == 0:
evenTotal += a
print evenTotal
Does this help?
Kinuthia...
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Re: [Tutor] Memroy Error - how to manage large data sets?
On Tue, 2008-07-29 at 12:00 +0200, [EMAIL PROTECTED] wrote: > Message: 2 > Date: Tue, 29 Jul 2008 08:44:40 +0100 > From: "Alan Gauld" <[EMAIL PROTECTED]> > Subject: Re: [Tutor] Tutor Digest, Vol 53, Issue 99 > To: tutor@python.org > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; format=flowed; charset="iso-8859-1"; > reply-type=original > > "kinuthiA muchanE" <[EMAIL PROTECTED]> wrote > > > I have realised that when you need to work with large numbers, > lists > > are > > slow and tend to gobble up bytes. > > The lists are not particularly slow (obviously if you want to > traverse them they take longer for more members) and they > don't take up much more memory that the sum of the sizes > of whats in them. > > The problem here is that the data items themselves are huge. > Around 20K per item. Thus a million times 20K is 20G! > > > This is how I would approach the problem, without using > > lists. > > Yep, we all seem to be pretty much in agreement :-) > > > It produces the result instantly, even for large numbers like a > > 100, 000, 000. > > Umm, not instantly on my PC... 1 million took 5 minutes, > I've no idea how long 100 million would take! I think the question is to calculate the sum of all even numbers in the Fibonacci series which do not exceed a million, not the millionth term. Number 25 on Project Euler which asks for first term in the Fibonacci series to contain 1000 digits, is the term-wise question ;) > > > def fibonacci() > >a = 0 > >b = 1 > >evenTotal = 0 > >while a < 1: > >a,b = b,a+b > >if a%2 == 0: > >evenTotal += a > >print evenTotal > > Alan G > > > > > ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tutor Digest, Vol 53, Issue 110
>
> Message: 5
> Date: Thu, 31 Jul 2008 09:07:22 -0400
> From: "S Python" <[EMAIL PROTECTED]>
> Subject: [Tutor] Reading List from File
> To: tutor@python.org
> Message-ID:
> <[EMAIL PROTECTED]>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Everyone,
>
> I am trying to read a comma-delimitted list ("aaa","bbb","ccc") from a
> text
> file and assign those values to a list, x, such that:
>
> x = ["aaa", "bbb", "ccc"]
>
> The code that I have come up with looks like this:
>
> >>> x = []
> >>> f = open(r'c:\test.txt', 'r')
> >>> x.extend(f.readlines())
> >>> x
> ['"aaa","bbb","ccc"']
>
> If you look closely, there is an extra pair of single quotes (') that
> encapsulates the string. Therefore, len(x) returns 1, instead of 3.
> Is
> there a function to "separate" this list out? I hope my question
> makes
> sense.
I think you are better off using the csv module. If you have a comma
separated file you could...
import csv
reader = csv.reader(open("some.csv", "rb"))
for row in reader:
print row
I yanked this straight out of the Python Reference Library :)
>
> Thanks in advance.
>
> Samir
> -- next part --
> An HTML attachment was scrubbed...
> URL:
>
>
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[Tutor] What has Editor X got that PyWin32 hasn't?
On Wed, 2008-08-13 at 16:59 +0200, [EMAIL PROTECTED] wrote: > > Message: 5 > Date: Wed, 13 Aug 2008 09:58:52 -0500 > From: "W W" <[EMAIL PROTECTED]> > Subject: Re: [Tutor] What has Editor X got that PyWin32 hasn't? > To: "Dick Moores" <[EMAIL PROTECTED]> > Cc: Python Tutor List > Message-ID: > <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="iso-8859-1" > > On Wed, Aug 13, 2008 at 9:42 AM, Dick Moores <[EMAIL PROTECTED]> wrote: > > > > > Since downloading vim 7.2 yesterday, I've had some trouble > distinguishing > > vim and gvim (both were included). Can you help me out? gvim is > GUI-vim, I > > think. Isn't that what I want to learn? Is gvim a cut-down version > of vim, > > but enables you to use your mouse ( :set mouse=a)? You can subscribe to vim mailing list by sending a blank email to [EMAIL PROTECTED] It is very friendly even for beginners, Bram Moolenaar, also gets to answer your questions sometimes! ;) > > > > As far as I know/have used, gvim is simply vim, but for lack of a > better > comparison, in its own terminal. The same thing you would have if you > were > to type "vim" at the command line. > > Honestly, the only thing I know how to do with the mouse in gvim is > paste > (middle click in linux). Or access the menus. That's one of the main > reasons > I /use/ vim - so I don't have to touch the mouse :) > > As far as any keyboard commands that I use, I've not seen any > difference > between vim, vi, and gvim. The main difference is syntax highlighting. > > -Wayne > > > ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
