'indent'ing Python in windows bat

[David Smith]

Hello, I'm essentially a newbie in Python.
My problem in searching the archives is not knowing what words to use to 
ask.


I'm converting windows bat files little by little to Python 3 as I find 
time and learn Python.

The most efficient method for some lines is to call Python like:
python -c "import sys; sys.exit(3)"

How do I "indent" if I have something like:
if (sR=='Cope'): sys.exit(1) elif (sR=='Perform') sys.exit(2) else 
sys.exit(3)


My sole result in many attempts is "Syntax Error."

Thank you for any help.

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Re: 'indent'ing Python in windows bat

[David Smith]

Thank you all. Roy Smith gets the most thanks, though he didn't answer 
my general question -- he showed me how to look at that specific 
structure differently. Terry Reedy might get thanks for her idea if I 
can ever figure the correct escape sequences that will make both windows 
and the Python interpreter happy. Bat makes bash/sed combos look like a 
breeze...


I thought you guys wouldn't want a treatise about WHY I was doing it 
this way and left it at one sentence. For whatever record, this is the 
sentence most missed.

I'm converting windows bat files little by little to Python 3 as I find time 
and learn Python.


I COULD stop doing all my other work to learn Python and convert all the 
batch files in one fell swoop. Efficiency? Fast way to get fired. Better 
to fit this in during the many small breaks I have. That's how the bat 
files were built over time in the first place. Or this email.


I COULD break down each batch file and write dozens of mini python 
scripts to be called. I already have a few, too. Efficiency? Speed is 
bad, but these are bat files, after all. The cost of trying to work with 
a multitude of small files is high, though, and I realized I had better 
go to a mix.


Some sections can be broken down to one liners. Efficiency? Speed is 
terrible, but it's far faster than typing commands. OTOH, I have the 
organization I need on the original bat file, which is slowly being 
rem'ed out. As I learn and have the time, the one-liners will melt 
together into a py file to be called from the bat file. Eventually, the 
bat will disappear back into the broken Window from whence it came.


Ugly, eh? I have under my belt scads of different languages from Fortran 
(using JCL!), Pascal, C++ to bash, sed, awk to Forth, assembly and a 
large cast of others. No big deal. My brain and Python, however, do NOT 
mix. I have been trying to learn the thing for over a decade and figure 
this will either force my brain into seeing the heart of the beast, or 
be swallowed in the attempt.


Bat files are ugly cripples, but even on Windows a two-legged quick and 
dirty dog is better than mistake-prone typing and button clicking. After 
conversion, I'm aiming to make these erstwhile ugly cripples fly when I 
find the time and as I stuff more Python down my gullet.


I agree. For those who have the unbroken time and understanding of 
Python, this is idiotic.


back to work,
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Re: Re: 'indent'ing Python in windows bat

[David Smith]

On 2012-09-19 05:22, Thomas Rachel wrote:

Am 18.09.2012 15:03 schrieb David Smith:


I COULD break down each batch file and write dozens of mini python
scripts to be called. I already have a few, too. Efficiency? Speed is
bad, but these are bat files, after all. The cost of trying to work with
a multitude of small files is high, though, and I realized I had better
go to a mix.


In order to achieve this, it might be very useful to either have a
module for each (bigger) part to be achieved which you can call with

...


Or you have one big "interpreter" which works this way:

class Cmd(object):
 """
 Command collector
 """

...
...


This is suitable for many small things and can be used this way:

...

Thomas


Thomas,
Beautiful. Gotta love it. I'll see if I can get the "interpreter" going. 
I particularly like it because I will be able to copy and paste 
wholesale when I stitch the final product back together again. Many thanks.


Going back to the one-liner, I discovered the following individual lines 
work:

print('hi')
if 1: print('hi')
print('hi');print('hi2')
if 1: print('hi');print('hi2')

but not:
print('hi');if 1: print('hi')

Chokes on the 'if'. On the surface, this is not consistent.

I'll drop the one-liners for now since I have something that I can work 
with as I learn to wrestle with Python.


thanks again.
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Re: Re: 'indent'ing Python in windows bat

[David Smith]

On 2012-09-19 14:18, Terry Reedy wrote:

stating correctly that it works for exec().


My mistake. I fancied you were talking shell, not python. I now see that 
Python 3 has exec() as a built-in.


python -c "exec('print(\"hi\")\nif 0:\n print(\"hi\")\nelif 1:\n 
print(\"hi2\")')"

worked right off the *.bat. Shades of sed!
Note I used a one space indentation. A tab works fine, too.


python -c "exec('print(%1)\nif 1: print(2)')"
and calling 'tem 3' prints
3
2
Thanks for the exhaustive study. :-) I'll keep it in mind. I hope I 
don't have to do this, though.



That said, if you have many multiline statements, putting them in a
separate file or files may be a good idea.


ASAP I'm hoping to have each bat swallowed completely by python. My 
current "bathon" or "pytch" file closes an old session then opens the 
session I select just like the bat mom used to bake.


Thank you again, Terry, and thanks to all -- even the *nix'ers. Might 
come in handy if I get back into that again.


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Re: How to apply the user's HTML environment in a Python programme?

[David Smith]

On 2012-09-21 08:57, BobAalsma wrote:

This text can be behind a username/password, but for several reasons, I don't 
want to know those.

So I would like to set up a situation where the user logs in (if/when 
appropriate), points out the URL to my programme and my programme would then be 
able to read that particular text.

I do this from a bat file that I will later translate to Python.
I tell my work wiki which file I want. I use chrome, so for every new 
session I'm asked for my credentials. However, that is all transparent 
to my bat file.


For that matter, when I download a new build from part of another bat 
file, I use Firefox and never see the credential exchange.


I wouldn't expect any different behavior using Python.

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Newbie question: Explain this behavior

[David Smith]

Why does code snippet one work correctly, but not two.  The only
difference is the placement of the "else".  I know that indentation
affects execution, but how does it change behavior in the following
examples?  Thank you.

1. for n in range(2, 10):
   for x in range(2, n):
  if n % x == 0:
 print n, 'equals', x, '*', n/x
 break
   else:
  # loop fell through without finding a factor
 print n, 'is a prime number'


Output:

2 is a prime number
3 is a prime number
4 equals 2 * 2
5 is a prime number
6 equals 2 * 3
7 is a prime number
8 equals 2 * 4
9 equals 3 * 3



2.  for n in range(2, 10):
for x in range(2, n):
   if n % x == 0:
  print n, 'equals', x, '*', n/x
  break
   else:
# loop fell through without finding a factor
  print n, 'is a prime number'

Output:

3 is a prime number
4 equals 2 * 2
5 is a prime number
5 is a prime number
5 is a prime number
6 equals 2 * 3
7 is a prime number
7 is a prime number
7 is a prime number
7 is a prime number
7 is a prime number
8 equals 2 * 4
9 is a prime number
9 equals 3 * 3

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Re: Newbie question: Explain this behavior - a followup

[David Smith]

First, thanks to those who offered answers.  They didn't really answer
my question, only because I had not worked through the example
sufficiently well.  Doing this, I believe I understand what is
happening, and, if my understanding is correct, have discovered that for
other beginning and ending values for the two range statements, the
example doesn't work.

Given that the beginning and ending values for the inner range statement
are the same, the inner range statement will never be executed for its
first iternation; the else will be.  This is not correct.  Simply make
the beginning value a non-prime number, and the program still prints out
that that number is prime.  Changing both beginning and ending values on
the two statements, the ouput is differentially buggy.


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Re: Newbie question: Explain this behavior - a followup

[David Smith]

max wrote:
> David Smith <[EMAIL PROTECTED]> wrote in
> news:[EMAIL PROTECTED]: 
> 
> 
>>range statements, the example doesn't work.
>>
>>Given that the beginning and ending values for the inner range
>>statement are the same, the inner range statement will never be
> 
> 
> Is your question about the semantics of for else blocks or about the 
> suitability of the algorithm given in the example? The for else block 
> is behaving exactly as expected...
> 
> 

Good question.  The question was directed at the latter, the suitability 
of algorithm for determining prime numbers.

>>>>range(1,1)
> 
> []
> 
>>>>range(500,500)
> 
> []
> 
> 
> see 
> http://groups-
> beta.google.com/group/comp.lang.python/browse_frm/thread/d6c084e791a00
> 2f4?q=for+else&hl=en&
> 
> for a good explanation of when the else part of the loop is executed. 
> Basically, whenever the loop is exited normally, which is what happens 
> when you iterate over an empty list like the one returned by 
> range(1,1)
> 
> 
> max
> 
> 
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Installing new version, erasing previous versions of Python

[David Smith]

I currently have Python 2.2 and 2.3.4 installed.  I want to install Python 2.4,
and erase 2.3.4, but retain 2.2, for I need it for my connectivity program.

According to the the documentation:

If you have a previous installation of Python that you don't want to replace
yet, use

make altinstall

the same set of files as "make install" except it doesn't create the hard link
to "python" named "python" and it doesn't install the manual page at
all."

And prior to this, it says:

All subdirectories created will have Python's version number in their
name, e.g. the library modules are installed in
"/usr/local/lib/python/" by default, where  is the
. release number (e.g. "2.1").  The Python binary is
installed as "python" and a hard link named "python" is
created.  The only file not installed with a version number in its
name is the manual page, installed as "/usr/local/man/man1/python.1"
by default.


If I understand the above correctly, 1) "make install" and "make altinstall" use
the same process, the only difference being the man page update, and the hard
link, and 2) that previous versions of python are not deleted.  Therefore I
should be able to install 2.4 without deleting 2.2.2.  If I wish to delete
2.3.4, I have to rm -r the appropriate directories.  Any caveats?  Is there any
crosstalk between 2.2.2 and 2.4 modules?  Thank you.
-- 
David Smith
1845 Purdue Ave #3
Los Angeles Calif 90025-5592
(310) 478-8050
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Re: Keeping the Console Open with IDLE

[David Smith]

W. eWatson wrote:
> Matimus wrote:
>> On Feb 19, 8:06 pm, "W. eWatson"  wrote:
>>> I'm using IDLE for editing, but execute programs directly. If there are
>>> execution or "compile" errors, the console closes before I can see
>>> what it
>>> contains. How do I prevent that?
>>> -- 
>>> W. eWatson
>>>
>>>   (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
>>>Obz Site:  39° 15' 7" N, 121° 2' 32" W, 2700 feet
>>>
>>>  Web Page: 
>>
>> Open a console window and type in the name of the script rather than
>> just double clicking on it. Or, you can terminate your script with a
>> 'raw_input("press enter to quit")'.
>>
>> Matt
> I can open the Python command line from Start, but how do I navigate to
> the folder where the program is?
> 

I'm not sure whether I should feel old or write a smart alec comment --
I suppose there are people in the world who don't know what to do with a
command prompt

Assuming a Windows system:

2. Type 'cd ' (as in Change Directory) in the command prompt window (w/o
the single quote characters)
3. Drag/drop the folder containing your python script to your command
prompt window
4. Hit enter in your command prompt window.
5. Type python my_script_name.py to execute my_script_name.py.

--David
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Re: Keeping the Console Open with IDLE

[David Smith]

W. eWatson wrote:
> 
>>
>> I'm not sure whether I should feel old or write a smart alec comment --
>> I suppose there are people in the world who don't know what to do with a
>> command prompt
>>
>> Assuming a Windows system:
>>
>> 2. Type 'cd ' (as in Change Directory) in the command prompt window (w/o
>> the single quote characters)
>> 3. Drag/drop the folder containing your python script to your command
>> prompt window
>> 4. Hit enter in your command prompt window.
>> 5. Type python my_script_name.py to execute my_script_name.py.
>>
>> --David
> If I enter just cd, then it tells me cd is not defined. If I enter
> c:/python25, it tells me I have a syntax error at c in c:. The title of
> the black background window I have up with a >>> prompt shown in it is
> "Python(command line)". Maybe this isn't the real Python console window?
> 
> What I want is that if I execute the program by double clicking on its
> name to display the console window with the program or syntax errors
> shown without it closing in a split second. Putting read_raw in it
> doesn't work, since some error prevents it from ever being seen.
> 

What I meant was open open the command prompt, type cd, space, DO NOT
hit enter yet.  Drag the folder with your script into the command prompt
window.  Then go to the command prompt window and hit enter.  This
should compose a command similar to the following:

C:\Documents and Settings\user> cd "C:\Documents and Settings\user\My
Documents\My Project"

C:\Documents and Settings\user\My Documents\My Project> _

--David
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Re: cross platform accessing paths (windows, linux ...)

[David Smith]

Vlastimil Brom wrote:
> 2009/3/13 hendra kusuma :
>> you may want to use os.sep to replace manually written "/" "\" ":" for each
>> os
>> I heard that unix/linux use "/" as directory separator while windows use "\"
>> and mac os use ":"
>>
> Thanks for the notice about the ":" path separator on mac;
> windows uses "\" but normally also accepts "/".
> Now I see, the diversity is yet greater, than I thought (cf.
> http://en.wikipedia.org/wiki/Path_(computing)
> 
> regards
>Vlasta

The ':' separator is for old Mac systems using Mac OS prior to version
10.0.  As of 10.0, they've moved to a unix based environment where the
path separator is now a '/' character.  There's been enough time passed
you'll have a very hard time finding one of the old systems.

--David
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Re: Python Goes Mercurial

[David Smith]

Kay Schluehr wrote:
> On 1 Apr., 07:56, Lawrence D'Oliveiro  central.gen.new_zealand> wrote:
>> In message <35d429fa-5d13-4703-
>>
>> a443-6a95c740c...@o6g2000yql.googlegroups.com>, John Yeung wrote:
>>> Here's one that clearly expresses strong antipathy:
>>>  http://mail.python.org/pipermail/python-dev/2009-March/087971.html
>> There are lots of GUI- and Web-based front ends to Git. And look at on-line
>> services like GitHub and Gitorious. The level of support for it is huge.
> 
> Ironically Mercurials most popular UI frontend Tortoise is going to
> crash Python tools ( like Wing-IDE ) on Windows. That's a known issue
> for about a year and more and the developers are not inclined to fix
> it. This doesn't really increase my trust that Mercurials UI tools are
> of a higher quality than Git's no matter which platform is used.

The conflict between TortoiseHg and Wing IDE can be fixed by simply
uninstalling the Tortoise Overlays.  You loose the graphic overlay on
folders, but otherwise everything works.

--David
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Re: Floor value in math operators

[David Smith]

Avi wrote:
> Hi,
> 
> This will be a very simple question to ask all the awesome programmers
> here:
> 
> How can I get answer in in decimals for such a math operator:
> 
> 3/2
> 
> I get 1. I want to get 1.5
> 
> Thanks in advance,
> Avi

I'm going to assume your operands are variables instead of numeric
literals.  Why not consider doing a type conversion to float or Decimal
and then perform the division?

--David
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Re: Floor value in math operators

[David Smith]

AggieDan04 wrote:
> On Apr 8, 12:08 pm, David Smith  wrote:
>> Avi wrote:
>>> Hi,
>>> This will be a very simple question to ask all the awesome programmers
>>> here:
>>> How can I get answer in in decimals for such a math operator:
>>> 3/2
>>> I get 1. I want to get 1.5
>>> Thanks in advance,
>>> Avi
>> I'm going to assume your operands are variables instead of numeric
>> literals.  Why not consider doing a type conversion to float or Decimal
>> and then perform the division?
> 
> Because float(x) and Decimal(x) fail for complex numbers and lose
> precision if x is a rational or a multi-precision float.

The OP didn't ask for anything complicated or high precision -- just
wanted to divide two integer values and get a float/Decimal output.

--David
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Re: Modifying the value of a float-like object

[David Smith]

eric.le.bi...@spectro.jussieu.fr wrote:
> It looks like what is needed here are a kind of "mutable float".  Is
> there a simple way of creating such a type?  I don't mind changing the
> value through x.value = 1.23 instead of x = 1.23... :)
> 
> On Apr 14, 3:03 pm, eric.le.bi...@spectro.jussieu.fr wrote:
>> Hello,
>>
>> Is there a way to easily build an object that behaves exactly like a
>> float, but whose value can be changed?  The goal is to maintain a list
>> [x, y,…] of these float-like objects, and to modify their value on the
>> fly (with something like x.value = 3.14) so that any expression like "x
>> +y" uses the new value.
>>
>> I thought of two solutions, both of which I can't make to work:
>>
>> 1) Use a class that inherits from float.  This takes care of the
>> "behave like float" part.  But is it possible to change the value of
>> the float associated with an instance?  That is, is it possible to
>> do:  "x = MyFloat(1.23); x.change_value(3.14)" so that x's float value
>> becomes 3.14?
>>
>> 2) The other possibility I thought of was: use a class that defines a
>> 'value' member (x.value).  This takes care of the "value can be
>> changed" part.  But is it possible/easy to make it fully behave like a
>> float (including when passed to functions like math.sin)?
>>
>> Alternatively, I'd be happy with a way of handling numerical
>> uncertainties in Python calculations (such as in "calculate the value
>> and uncertainty of a*sin(b) knowing that a=3.0 +/- 0.1 and b=1.00 +/-
>> 0.01").
>>
>> Any idea would be much appreciated!
> 

I think you'll have to describe your use case a little better.  I don't
see why you'd need a mutable float.  As long as the reference x is
visible to the other parts of your code, when that code uses x, it'll
always get the right instance of a float object.


--David
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Re: How to locate the bit in bits string?

[David Smith]

Li Wang wrote:
> 2009/4/29 Tim Chase :
>> Li Wang wrote:
>>> Hi:
>>>
>>> If I use an integer to represent bits:
>>> e.g. 99 represents '1100011'
>>>
>>> How can I locate, say the second bit of 99(i.e. '1')?
>>>
>>> Although bin(99)[4] could be used to locate it, this transform cost
>>> too much memory (99 only needs 2Bytes, while string '1100011' needs
>>> 7Bytes).
>>>
>>> Anyone knows how to locate  the second bit without using bin() function?
>> You mean
>>
>>  def get_bit(number, bit):
>>return (number >> bit) & 1
>>
>> ?
>>
> Hummm, I have tried this method too, the problem is its time
> complexity. If the length of my bits is n, then the time complexity is
> O(n). When I tried to implement this in practice, it did consume a lot
> of time.
> 
> So do you know how could I locate the bit in O(1) time? Transform it
> into a string is a method, but takes too much space (when I try to
> process a 2M file, it used more than 100M memory.).
> 
> Thank you very much.
> 
>> -tkc
>>
>>

So... I can only conclude you are looking for bit x in the entirety of a
file.  First you'll have to figure out what byte to look at w/ a little
integer division, then read to that point and test for the specific bit
-- I'm thinking a bitwise and operation with a bit mask.  Should be
really fast.


--David
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Re: Python Noob - a couple questions involving a web app

[David Smith]

Kyle T. Jones wrote:
> Bruno Desthuilliers, my dear, dear friend, there was this time, oh,
> 4/29/2009 3:02 AM or thereabouts, when you let the following craziness
> loose on Usenet:
>> Kyle T. Jones a écrit :
>>> Been programming for a long time, but just starting out with Python.
>>> Not a professional programmer, just that guy in one of those
>>> organizations that won't hire a pro, instead saying "Hey, Kyle knows
>>> computer stuff - let's have him do this (and that, and the other, etc)".
>>>
>>> So, the higher ups want a web app that'll let them enter (from an
>>> intranet page) a rather simple, but quite lengthy, list - details to
>>> be stored in a MySQL database... just normal stuff here, entering,
>>> editing, and deleting entries, sorting, etc.
>>>
>>> On the internet side of things, folks get the info served up to them,
>>> can sort it in a few ways, etc - it's pretty basic stuff.
>>>
>> (snip)
>>
>> I can only second Arnaud and Emile : Django is very probably what
>> you're looking for, and by all means better than any PHP thingie -
>> wrt/ both development time and security.
>>
>> You'll indeed first have to learn the framework (and Python of
>> course), and learn how to deploy your app in production (which can be
>> a bit tricky if you're not familiar with server admin), but there's a
>> good documentation and a very helpful community around both the Django
>> framework and the Python language.
>>
> 
> Thanks everyone!  Wow, pretty much a consensus - a rarity with these
> "types" of questions, at least in my experience.
> 
> Ok, sounds like I need to be looking at Django.  Thanks for the advice!
> 
> Cheers!

Consensus?! ... that just won't do. :-)

I've started with Pylons and have found it very nice.  Loose enough to
tinker with the inner workings but complete and working right out of the
box (or paster in Pylons case).

--David
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Re: How to walk up parent directories?

[David Smith]

Matthew Wilson wrote:
> Is there already a tool in the standard library to let me walk up from a
> subdirectory to the top of my file system?
> 
> In other words, I'm looking for something like:
> 
> >>> for x in walkup('/home/matt/projects'):
> ... print(x)
> /home/matt/projects
> /home/matt
> /home
> /
> 
> I know I could build something like this with various os.path
> components, but I'm hoping I don't have to.
> 
> TIA
> 
> 
> Matt

You should take a look at the os.path module.  Seems like you might find
something in that toolbox for this.

--David
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Re: What text editor is everyone using for Python

[David Smith]

Lacrima wrote:
> I am new to python.
> And now I am using trial version of Wing IDE.
> But nobody mentioned it as a favourite editor.
> So should I buy it when trial is expired or there are better choices?


I use Wing IDE and like it.  It very nicely enforces consistent space
indentations and other Python basics that might fall through the cracks
when writing.  I'm not too hot on the auto-suggest, but I haven't seen
any other IDE do better.

--David
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Re: SAX: Short tag's ...

[David Smith]

Thomas Lehmann wrote:
> Hi!
> 
> Is there a way to recognize short tags in a XML?
> I'm implementing a SAX handler...
> 
> Problem: storing the XML code I would need this information
> in the startElement ...
> 
> How can I handle this?
> 
> 
> any text

So ... are you writing as you read?  If so, I'm not sure you can know
which form to write out immediately.  Best bet would be to delay write
until the next SAX event.  The next SAX event will tell if the element
should be written as  or .

--David
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Re: logging of strings with broken encoding

[David Smith]

Thomas Guettler wrote:
> Hi,
> 
> I have bug in my code, which results in the same error has this one:
> 
> https://bugs.launchpad.net/bzr/+bug/295653
> {{{
> Traceback (most recent call last):
>   File "/usr/lib/python2.6/logging/__init__.py", line 765, in emit
> self.stream.write(fs % msg.encode("UTF-8"))
>   ..
> UnicodeDecodeError: 'ascii' codec can't decode byte 0xe4 in position 8: 
> ordinal not in range(128)
> }}}
> 
> I run Python 2.6. In SVN the code is the same (StreamHandler ... def emit...):
> http://svn.python.org/view/python/branches/release26-maint/Lib/logging/__init__.py?revision=72507&view=markup
> 
> I think msg.encode("UTF-8", 'backslashreplace') would be better here.
> 
> What do you think?
> 
> Should I fill a bugreport?
> 
>   Thomas
> 
> 

I think you have to decode it first using the strings original encoding
whether that be cp1252 or mac-roman or any of the other 8-bit encodings.
 Once that's done, you can encode in UTF-8

--David
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Re: Clarity vs. code reuse/generality

[David Smith]

kj wrote:
> In <7x4otsux7f@ruckus.brouhaha.com> Paul Rubin 
>  writes:
> 
>> kj  writes:
>>> sense = cmp(func(hi), func(lo))
>>> assert sense != 0, "func is not strictly monotonic in [lo, hi]"
> 
>> bisection search usually just requires the function to be continuous
>> and to have its value cross the target somewhere between the endpoints,
>> not be monotonic.
> 
> Try the algorithm I posted with lo = -pi/4, hi = 2*pi, func = cos,
> target = -1, and see what you get...
> 
>>> I regard the very special case of func(hi)==func(lo)==target as
>>> pathological (analogous to the fact that a stopped watch is "exactly
>>> right" twice a day), and not one I care to support.
> 
>> I do think you should support that case, under the "do 'nothing'
>> gracefully" principle.
> 
> You keep missing the point that this is an *internal* *helper*
> *convenience* function, meant to abstract away common logic from
> a handful of places and thus eliminate some code repetition within
> a module.  It is *not* a library function intended to be called
> from elsewhere.  So talk of "supporting" anything is besides the
> point.  Any internal use of this function that applies it to a
> non-strictly-monotonic function is, by assumption, an error.
> 
> kj

First, let me say *I got the point*.  I use asserts, but only in unit
testing where I want to test the result of some action for correctness.
 In the course of programming product code, I personally don't think
they should ever be used exactly for the reasons everyone else is
pointing out.  They can be disabled with the -O option and that changes
the program's behavior in ways that could break in production.

If you insist on teaching the assert statement, teach it in the context
of writing unit testing code.  Its an extremely valuable skill.

--David
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Re: tkinter problem

[David Smith]

Paul Simon wrote:
> "Peter Otten" <__pete...@web.de> wrote in message 
> news:h3481q$d95$0...@news.t-online.com...
>> Paul Simon wrote:
>>
>>> "Chris Rebert"  wrote in message
>>> news:mailman.2863.1247095339.8015.python-l...@python.org...
>>> On Wed, Jul 8, 2009 at 4:18 PM, Paul Simon wrote:
 I have the "tkinter" problem and need some assistance to straighten it
 out.
 >From the web page "http://wiki.python.org/moin/TkInter"; I tested as in
> "step
 1" and cannot import "_tkinter." I do not have that file on my computer,
 but
 do have tkinter.py in /usr/local/lib/python2.6/lib-tk. as well as the
 directories /usr/lib/tk8.5 and /usr/lib/tcl8.5.
 This python stuff is great, but the documentation frequently
 feels like it is just a bit out of my grasp. I realize that all of this
 is free but I understand the instructions on the web page to repair only
 to the
 point of confusion. I'm not an expert. How do I modify my python
 configuration? Is there a file that needs to be edited? Which setup.py
 file
 do I use? Make? or python setup.py build and python setup.py install?
 Thanks. I appreciate your help.
>>> - How did you install Python?
>>> - What Linux distro are you using?
>>>
>>> Cheers,
>>> Chris
>>> http://blog.rebertia.com
>>> I"m using Mandriva 2008.1.  I have to tell you honestly that I'm not sure
>>> exactly how I installed Python.  Originally I had installed 2.5 from RPM
>>> but 2.6 was not available for my distro (2008.1) in RPM.  I downloaded
>>> something from python.org and installed.  Not sure if it was tarball or
>>> zip file.
>> Zip or tar doesn't matter, you are installing "from source".
>>
>> Python has to find the necessary include files for tcl/tk. These are in
>> separate packages that you have to install before you invoke Python's
>> configure script.
>>
>> I don't know what they are called on your system -- look for tk-dev.rpm,
>> tcl-dev.rpm or similar.
>>
>> You may run into the same problem with other modules like readline.
>>
>> Peter
>>
> 
> Thank you Peter.  I understand what you are saying but don't know how to do 
> it.  Although I installed from source, I followed a "cookbook" recipe. 
> Could you tell me what files to execute, where they might be, and file 
> arguments?  I'm just ignorant, not stupid. ;-).
> 
> Paul 
> 
> 

Just install the tkinter package from the Mandriva Linux Control
Center's Software Management system.  I just did it, doing a search for
tkinter brought it right up.  All done.

--David
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Re: Python code for testing well parenthesized expression

[David Smith]

Jeremy Sanders wrote:
> candide wrote:
> 
>> I'm trying to implement in Python a function testing if an expression is
>> well parenthesized. For instance the expression "zx4er(1(er(Yy)ol)ol)ik"
>> is correctly parenthesized but this one "zx(4er(1(er(Yy)ol)ol)ik" is not.
>>
>> My code follows at the end.
>>
>> If you have a better algorithm or a better Python code (I'm a beginner in
>> the Python world), don't hesitate ...
> 
> Don't you want to just test that the number of "("s equals the number of 
> ")"s or am I missing the point?
> 
 a='aAAA(bbb(cc)))'
 a.count('(') == a.count(')')
> 
> Jeremy
> 

Using straight counting, )z))ab(c(ew( would be well parenthesized.  I
suspect a better way would be to iterate over the string using a balance
counter that increases 1 for every open, decreases 1 for every close.  A
negative balance at any moment would indicate an error as well as an
ending balance greater than 0.

--David
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Re: Help understanding the decisions *behind* python?

[David Smith]

Piet van Oostrum wrote:
>> Hendrik van Rooyen  (HvR) wrote:
> 
>> HvR> On Monday 20 July 2009 21:26:07 Phillip B Oldham wrote:
 On Jul 20, 6:08 pm, Duncan Booth  wrote:
> The main reason why you need both lists and tuples is that because a
> tuple of immutable objects is itself immutable you can use it as a
> dictionary key.
 Really? That sounds interesting, although I can't think of any real-
 world cases where you'd use something like that.
> 
>> HvR> simplest is something like a point in the cartesian plane with
>> HvR> an associated attribute like colour.
> 
> There are numerous other examples. Anytime you need a key that is not a
> single object but composed of more than one:
> Name + birthday
> Street + number + City
> Student + Course
> etc.

Compound keys (like what's listed above) can also be used for sorting
lists of dictionaries using DSU style sorting.  Something I believe (and
 I could be wrong) won't work with mutable types like lists.

--David
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Re: If Scheme is so good why MIT drops it?

[David Smith]

Aahz wrote:
> In article ,
> Hendrik van Rooyen   wrote:
>> On Sunday 26 July 2009 21:26:46 David Robinow wrote:
>>>  I'm a mediocre programmer. Does this mean I should switch to PHP?
>> I have searched, but I can find nothing about this mediocre language.
>>
>> Could you tell us more?
> 
> :-P
> 
> (For anyone who is confused by Hendrik's humor, he is saying that David
> was referring to a programming language named "mediocre".  English
> grammar is confusing!)

LOL ... I'm an American and that wasn't all that clear :-)
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Re: Questions on XML

[David Smith]

joy99 wrote:
> Dear Group,
> 
> I like to convert some simple strings of natural language to XML. May
> I use Python to do this? If any one can help me, on this.
> 
> I am using primarily UTF-8 based strings, like Hindi or Bengali. Can I
> use Python to help me in this regard?
> 
> How can I learn good XML aspects of Python. If any one can kindly name
> me a book or URL.
> 
> I am using Python2.6 on Windows XP with IDLE as GUI.
> 
> Best Regards,
> Subhabrata.

Take a look at xml.etree.ElementTree package and it's contents.  It's
included in the binary distributions of Python 2.6.  There are lot's of
books out covering XML and UTF-8 is exactly where you want to be w/ XML.

--David
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Re: Question on the "csv" library

[David Smith]

vsoler wrote:
> 
> Thank you very much for all your comments. After reading them I can
> conclude that:
> 
> 1- the CSV format is not standardized; each piece of software uses it
> differently

True, but there are commonalities.  See
http://en.wikipedia.org/wiki/Comma-separated_values

> 
> 2- the "C" in "CSV" does not mean "comma" for Microsoft Excel; the ";"
> comes from my regional Spanish settings

The C really does stand for comma.  I've never seen MS spit out
semi-colon separated text on a CSV format.

> 
> 3- Excel does not even put quotes around litteral texts, not even when
> the text contains a blank

There is no need to quote text literals with whitespace in them.  There
is a need when a newline exists or when the separator character is
embedded in the field.


--David
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Re: obscure problem using elementtree to make xhtml website

[David Smith]

Lee wrote:
> Elementtree (python xml parser) will transform markup like
> 
> 
> 
> into
> 
> 
> 
> which is a reasonable thing to do for xml (called minimization, I
> think).
> 
> But this caused an obscure problem when I used it to create the xhtml
> parts of my website,
> causing Internet Explorer to display nearly blank pages. I explain the
> details at
> 
> http://lee-phillips.org/scripttag/
> 
> and am writing here as a heads-up to anyone who might be using a
> workflow similar to mine: writing documents in xml and using python
> and elementtree to transform those into xhtml webpages, and using the
> standard kludge of serving them as text/html to IE, to get around the
> latter's inability to handle xml. I can't be the only one (and I doubt
> this problem is confined to elementtree).
> 
> 
> Lee Phillips

It's not just Elementtree that does this .. I've seen others libraries
(admittedly in other languages I won't mention here) transform empty
tags to the self-terminating form.  A whitespace text node or comment
node in between *should* prevent that from happening.  AFAIK, the only
tag in IE xhtml that really doesn't like to be reduced like that is the
 tag.  Firefox seems to be fine w/ self-terminating