Re: Problem using pip

[Jerry Hill]

On Tue, Jan 14, 2020 at 2:18 AM proplayer raj
 wrote:
>
> dear team
> I have encountered a problem while using pip , that it did not allowed to
> install webbrowsing and OS module it show the error that it does not found
> any matching distributor and does not fount the version which can fulfill
> the requirement.

Can you be specific about which modules you are trying to install?  I
don't see any sign of a python package called 'webbrowsing' anywhere
on the internet, for instance.  Are you possibly looking for the
'webbrowser' module?  If so, it's not installed via pip, it's part of
the python standard library (see docs here:
https://docs.python.org/3/library/webbrowser.html).  There's also an
'os' module in the standard library
(https://docs.python.org/3/library/os.html). Are those the modules you
were looking for?

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Re: Python Console Menu

[Jerry Hill]

On Tue, Jul 31, 2018 at 12:31 PM juraj.papic--- via Python-list
 wrote:
> I will check the links thanks for that tips, is there any page where I can 
> see more examples?

I like Doug Hellmann's Python Module of the Week site for in-depth
looks at particular modules (including subprocess).  If you're using
python 3, the subprocess module's page is here:
https://pymotw.com/3/subprocess/.

>From your sample code, you may still be using python 2.  If so, the
PyMOTW page for that version is here:
https://pymotw.com/2/subprocess/.

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Re: Missing python36.dll

[Jerry Hill]

On Mon, Mar 19, 2018 at 5:07 PM, MRAB  wrote:

> You didn't say which installer you used.
>

​It might also be helpful to know:

Did you install python for "Just Me" or "All Users" in the installer?

Does the user you're logged in as have enough authority to install for All
Users if that's what you picked?

What OS ​are you using?  Since you're asking about DLLs, it's obviously
some flavor of Windows, but you don't say which one.

Did you notice any errors messages or log files generated by the installer?
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Re: Can't Uninstall !

[Jerry Hill]

On Tue, Feb 13, 2018 at 10:30 AM, Pedro Crescencio 
wrote:

3. How did you try to uninstall it?
> Using Windows standard uninstall procedure
> https://www.windowscentral.com/how-to-uninstall-apps-windows-10
>

​That page describes two different ways of uninstalling programs (from the
start screen, or from the Apps & Features control panel).  I don't know if
it matters, but it might help someone to know which one you used.​


> 4. What messages did you get when you tried to uninstall it?
> The message says : "Uninstalled". But I still have the icon over the App
> list.
>

​You say you have "the" icon.​

​What icon is that? A normal python install should have a bunch of
different stuff on the start menu -- on the Windows 7 installation ​I have
in front of me, I have a "Python 3.6" folder, with four different links
nested inside - "IDLE (Python 3.6 32-bit)", "Python 3.6 (32-bit)", "Python
3.6 Manuals (32-bit)", and "Python 3.6 Module Docs (32-bit)".  What do you
have?

​When you installed python, do you remember if you installed it for "All
Users" or "Just Me"?​

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Re: replacing `else` with `then` in `for` and `try`

[Jerry Hill]

On Wed, Nov 1, 2017 at 5:12 PM, Alexey Muranov 
wrote:

> what do you think about the idea of replacing "`else`" with "`then`" in
> the contexts of `for` and `try`?
>

​I wish the core python developers​ had done it 20 years ago.  Given that
python is a relatively mature language at this point, I don't expect that
it will ever change.

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Re: Finding keyword arguments in the documentation

[Jerry Hill]

On Tue, Sep 26, 2017 at 12:32 PM, Peter Otten <__pete...@web.de> wrote:
> Newer Python versions will show
>
> Help on built-in function sin in module math:
>
> sin(x, /)
> Return the sine of x (measured in radians).
>
>
> where the arguments before the slash are positional-only:

What version of python do you need to see that output from help?  I'm
not seeing it in 3.6.1 on windows:

Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 17:54:52) [MSC v.1900 32
bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import math
>>> help (math.sin)
Help on built-in function sin in module math:

sin(...)
sin(x)

Return the sine of x (measured in radians).

>>>

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Re: [Tutor] beginning to code

[Jerry Hill]

On Tue, Sep 19, 2017 at 8:26 PM, Rick Johnson
 wrote:
> In the spirit of my last comment, i was going to say: "Or if
> `x` does not support rich comparisons", but alas, it seems that
> _all_ objects in Python support rich comparisons, even when
> it doesn't make sense to! o_O For example:
>
> >>> False > 1
> False
> >>> dir > 1
> True
> >>> isinstance < 100
> False
> >>> "" >= 10
> True
> >>> (1,) <= 500
> False

Rick, I'm pretty sure you already know that you're being deceptive
here.  If anyone else comes across this and doesn't already realize
it, note that Rick is complaining about behavior that changed almost a
decade ago (with the release of Python 3.0).

Here's what a modern python does with those same statements:

Python 3.5.2 (default, Aug 18 2017, 17:48:00)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> False > 1
False
>>> dir > 1
Traceback (most recent call last):
  File "", line 1, in 
TypeError: unorderable types: builtin_function_or_method() > int()
>>> isinstance < 100
Traceback (most recent call last):
  File "", line 1, in 
TypeError: unorderable types: builtin_function_or_method() < int()
>>> "" >= 10
Traceback (most recent call last):
  File "", line 1, in 
TypeError: unorderable types: str() >= int()
>>> (1,) <= 500
Traceback (most recent call last):
  File "", line 1, in 
TypeError: unorderable types: tuple() <= int()
>>>

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Re: If you are running 32-bit 3.6 on Windows, please test this

[Jerry Hill]

On Wed, Aug 30, 2017 at 1:48 PM, MRAB  wrote:
>
> On 2017-08-30 18:35, Terry Reedy wrote:
>>
>> https://stackoverflow.com/questions/45965545/math-sqrt-domain-error-when-square-rooting-a-positive-number
>>
>> reports the following:
>> -
>> Microsoft Windows [Version 10.0.16251.1002]
>> (c) 2017 Microsoft Corporation. All rights reserved.
>>
>> C:\Users\Adam>python
>> Python 3.6.2 (v3.6.2:5fd33b5, Jul  8 2017, 04:14:34) [MSC v.1900 32 bit
>> (Intel)] on win32
>> Type "help", "copyright", "credits" or "license" for more information.
>>   >>> import math
>>   >>> math.sqrt(1.3)
>> Traceback (most recent call last):
>>File "", line 1, in 
>> ValueError: math domain error
>>   >>>
>>
>> I upgraded from version 3.6.1 to 3.6.2 to try to resolve the issue and
>> restarted my computer but it is still occurring. Some numbers are
>> working (1.2, 1.4) and some others are also not working (1.128).
>> 
>>
>> Neither installed 64 bit 3.6.2 nor my repository 3.6 32-bit debug build
>> reproduce this.  If anyone has the python.org 32bit 3.6.1/2 releases
>> installed on Windows, please test and report.
>>
> Python 3.6.2 (v3.6.2:5fd33b5, Jul  8 2017, 04:14:34) [MSC v.1900 32 bit 
> (Intel)] on win32
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import math
> >>> math.sqrt(1.3)
> 1.140175425099138
> >>>
>
> This is on 64-bit Windows 10.
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This all seems to work fine with python 3.6.1 on Windows 7 (64-bit OS,
32-bit python).

Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 17:54:52) [MSC v.1900 32
bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import math
>>> math.sqrt(1.3)
1.140175425099138
>>>

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Re: how to write add frequency in particular file by reading a csv file and then making a new file of multiple csv file by adding frequency

[Jerry Hill]

On Fri, Jun 23, 2017 at 4:07 PM, Mark Byrne  wrote:

> Possible fix is to replace this:
>
> count = frequency.get(word,0)
> count1 = frequency.get(word1,0)
> if word1 == word:
> frequency[word] = count + count1
> else:
> frequency[word] = count
>
> with this:
>
> if word1 == word:
> if word in frequency:
> frequency[word] += 1
> else:
> frequency[word] = 1
>

Have you considered replacing your frequency dict with a
defaultdict(int)​?  That way you could boil the whole thing down to:

from collections import defaultdict
frequency = defaultdict(int)
...

...
if word1 == word:
frequency[word] += 1

The defaultdict takes care of the special case for you.  If the value is
missing, it's defaulted to 0.

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Re: Two variable dictionary comprehension

[Jerry Hill]

On Mon, Apr 3, 2017 at 5:50 PM, Deborah Swanson
 wrote:
> Ah, but did you actually try to use the proposed solutions on the two
> stackoverflow pages? It's been several weeks now, but I did, and neither
> of those two examples fit my situation, which is why I ended up writing
> my own, and unsatisfactorily at that.

Well, that first Stack Overflow link has the following as the first
part of the highest scored answer:

  In Python 2.6 and earlier, the dict constructor can receive an
iterable of key/value pairs:
  d = dict((key, value) for (key, value) in iterable)

  From Python 2.7 and 3 onwards, you can just use the dict
comprehension syntax directly:
  d = {key: value for (key, value) in iterable}

Isn't that second form the exact thing you were looking for, back in
your first post?

> I'm sorry you think the current edition of Google does such a fine job.
> Has it really been that many years ago that the results Google returned
> from a  properly formatted boolean search were really useful? I'd
> imagine that the old Google would have returned a good 10 pages or more
> (probably a lot more) of urls containing the phrase "dict comprehension"
> or "dictionary comprehension". in which you'd find a rich variety of
> specific situations to glean through. (You wouldn't have needed to
> include "python" in the search phrase, since no other programming
> language that I know of, or other English usage for that matter, has
> dict comprehensions.)

Is this not your experience today?  I just browsed through the first 5
pages of search results for the phrase "dict comprehension" (without
the quotes), and the results seem to be pretty on point.  It's mostly
results talking about python dict comprehensions, general python pages
talking about all sorts of comprehensions (dict, list, and set), and
as you get deeper into the result pages, you start to see some entries
for the word "comprehension" in dictionaries too, which seems like a
reasonable thing to end up mixed in with the desired results.  It goes
on in that vein out to page 11 or so, at which point things seem to
devolve a bit.

I'd be totally sympathetic with your plight if you didn't know the key
phrase 'dict comprehension' to find all of that information.  I'm just
not seeing the poor results you seem to be getting from Google once
you know the term.

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Re: Two variable dictionary comprehension

[Jerry Hill]

On Mon, Apr 3, 2017 at 10:30 AM, Deborah Swanson
 wrote:
> Regular updates as the docs are updated would be a good idea too. It's
> obvious that today's Google isn't up to it, although it occurs to me
> that I haven't tried Google's site search on python.org.

So, when you search google for the phrase "dict comprehension" or
"dictionary comprehension", nothing useful comes up for you?  When I
search either of those phrases, I get lots of useful results, all of
which spell out how to do what you were originally asking about.  I
know Google search results are skewed by past usage, but I'm surprised
that you didn't find anything useful in the first couple of search
results.

When I do a search for 'dict comprehension' I get a boxed result
linking to PEP 274 as the first hit, then two Stack Overflow
questions, both of which demonstrate how to do dictionary
comprehensions.  Following that is another link to PEP 274, a link to
the Python docs on data structures (which does talk about dict
comprehensions, but it's way down on the page), and then links to a
bunch of tutorials.  If you had to judge based on my search results,
Google does a fine job of answering python questions, at least when
you already know the key phrase to look for.

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Re: how to evaluate a ast tree and change Add to Multiply ?

[Jerry Hill]

On Wed, Oct 12, 2016 at 5:55 AM, meInvent bbird  wrote:
> i just expect to
> rewrite + become multiply
> by edit the example in the link provided

This seems to work.  You need to define visit_BinOp instead of
visit_Num (since you want to mess with the binary operations, not the
numbers).  Then,in visit_BinOp, we just replace the ast.Add node with
an ast.Mult node.

import ast

class ChangeAddToMultiply(ast.NodeTransformer):
"""Wraps all integers in a call to Integer()"""
def visit_BinOp(self, node):
if isinstance(node.op, ast.Add):
node.op = ast.Mult()
return node

code = 'print(2+5)'
tree = ast.parse(code)
tree = ChangeAddToMultiply().visit(tree)
ast.fix_missing_locations(tree)
co = compile(tree, '', "exec")

exec(code)
exec(co)

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Re: Why don't we call the for loop what it really is, a foreach loop?

[Jerry Hill]

On Tue, Sep 13, 2016 at 4:57 PM,   wrote:
> It would help newbies and prevent confusion.

Are you asking why Guido didn't call it foreach back in 1989, or why
the core developers don't change it now, 27 years later?  I can't
speak for the historical perspective, but I'm sure there's basically
no chance that it will be changed now.  It would be a totally
backwards incompatible change, invalidate every tutorial and bit of
python documentation that's been written over the last three decades,
and break pretty much every python program that works today. In
exchange, you get newbies who are a slightly less confused about for
loops.  That tradeoff isn't worth it.

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Re: Text input with keyboard, via input methods

[Jerry Hill]

On Thu, Mar 10, 2016 at 5:51 AM, Marko Rauhamaa  wrote:
> I don't have an answer. I have requirements, though:
>
>  * I should be able to get the character by knowing its glyph (shape).
>
>  * It should be very low-level and work system-wide, preferably over the
>network (I'm typing this over the network).

This probably doesn't meet all your needs, but there are web services
that get you to draw an approximation of a glyph, then present you
with some possible unicode characters to match. I thought there were a
couple of these sites, but on a quick search, I only find one for
unicode glyphs: http://shapecatcher.com/  and another one for TeX
codes: http://detexify.kirelabs.org/classify.html

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Re: Need Help w. Getting the Eclipse Python Add-On.

[Jerry Hill]

On Fri, Jul 17, 2015 at 2:22 PM, Steve Burrus steveburru...@gmail.com wrote:
 I Need immediate Help w. Getting the Eclipse Python Add-On. I looked all 
 around the Eclipse website to try to get this but didn't see the add-on for 
 this. Can someone please help me to find it? Thanx.

I think you're looking for PyDev: http://www.pydev.org/

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Re: What means -?

[Jerry Hill]

On Tue, Apr 28, 2015 at 1:18 PM,  stehlam...@arcor.de wrote:
 in the Python Language Specification, I've found the delimiter - (cf.
 https://docs.python.org/3/reference/lexical_analysis.html#delimiters, last
 entry in the table´s second line). Could you please describe the effects of
 this delimiter? I read nothing about - by now. In addition, help(-)
 didn´t work.

It's part of the syntax for function annotations.

See here in the reference manual:
https://docs.python.org/3/reference/compound_stmts.html#index-23
and/or refer to PEP 3107 for more background:
https://www.python.org/dev/peps/pep-3107/

If you're interested, PEP 484
(https://www.python.org/dev/peps/pep-0484/) is attempting to chart out
the future uses of function annotation for doing type checking in
external tools (keep in mind that PEP 484 isn't final yet, nor has it
been accepted, my impression is that it's still a work in progress).

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Re: Anyone used snap.py for drawing a graph?

[Jerry Hill]

On Sun, Apr 12, 2015 at 10:29 PM, Pippo adm2303.2...@gmail.com wrote:
 Any guide on this?

 http://snap.stanford.edu/snappy/#download

Sure.  http://snap.stanford.edu/snappy/#docs
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Re: Automation of Windows app?

[Jerry Hill]

On Fri, Mar 20, 2015 at 2:10 PM, Grant Edwards invalid@invalid.invalid wrote:
 I need to automate operation of a Windows application.

I've used Sikuli (http://www.sikuli.org/) for similar things in the
past.  It's an automation framework built on Jython, and it worked
great for what I needed at the time.

I think AutoHotKey is also widely used for automating windows GUI
apps, but it's not related to python at all.

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Re: html page mail link to webmail program

[Jerry Hill]

On Tue, Nov 11, 2014 at 8:04 PM, Ethan Furman et...@stoneleaf.us wrote:
 My wife (using a Win7 machine) will be on a web page that has a link to mail
 somebody.  She clicks on it, and it opens the currently installed but unused
 Thunderbird.

As others have mentioned, this is more a question of configuring your
browser than anything involving python.

That said, those links on a web page that open an email window are
called mailto links.  A google search for open mailto links in
gmail (without the quotes) gets a bunch of general information, and
if you add your wife's browser of choice to the search terms, you
should get some explicit instructions for setting everything up
properly.

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Re: NumPy, SciPy, Python 3X Installation/compatibility issues

[Jerry Hill]

On Tue, Sep 23, 2014 at 1:54 PM, SK shagunkh...@gmail.com wrote:
 Hi EK,
 Did you figure out questions 1, 2 and 3? SciPy (0.14.0) on installation asks 
 me for Python 2.7. First day on Python here, I am really struggling :/
 Thanks,
 SK

Did you download the SciPy installer for python 3.3?  I see it listed
for download on the sourceforge site here:
http://sourceforge.net/projects/scipy/files/scipy/0.14.0/scipy-0.14.0-win32-superpack-python3.3.exe/download

There are also versions for python 3.4, 3.2, 2.7 and 2.6, so you have
to make sure you get the one that matches the version of python you're
using.

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Re: .Net Like Gui Builder for Python?

[Jerry Hill]

On Fri, Jul 25, 2014 at 10:55 AM, Orochi kartikjagdal...@gmail.com wrote:
 So,Is there any Gui App builder like Visual Studio or having features like 
 Visual Studio for Python.

I'm not aware of anything with the same level of functionality as
Visual Studio's GUI building tools.  Glade is the closest I've seen,
and as you mentioned, it's not as interactive and integrated into an
IDE as Visual Studio is.

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Re: Question about Pass-by-object-reference?

[Jerry Hill]

On Tue, Jul 22, 2014 at 6:17 PM, fl rxjw...@gmail.com wrote:
 Thanks for your example. I do not find the explanation of [:] on line. Could 
 you
 explain it to me, or where can I find it on line?

It's pretty hard to find if you don't already know what's going on.

First, you need to know that mylst[i:j] refers to a slice of  the list
mylist.  Specifically, the items from the list starting with the
item at index i, up to but not including the item at index j.  If you
leave the i off (e.g., mylist[:j]) that's a slice from the start of
the list up to (but not including) the j-th item.  If you leave the
end position off, (e.g., mylist[i:]), that gets you the i-th item to
the end (including the last item).  If you leave off both indexes from
the slice, you get back the entire contents of the list.  So that's
what mylist[:] means.

Then you need to know that you can assign to the slice and it will
replace the old elements from the slice with the new ones.  You can
see that defined here, in the docs (second item in the table under
4.6.3. Mutable Sequence Types):

https://docs.python.org/3/library/stdtypes.html#mutable-sequence-types

So, when you so mylist[:] = [0,1] you're taking all of the contents of
the existing list, and replacing them with the contents of the list
[0,1].  That changes the existing list, it doesn't just assign a new
list to the name mylist.

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Re: Error while calling round() from future.builtins

[Jerry Hill]

On Sat, May 10, 2014 at 7:39 AM, Preethi preethid...@gmail.com wrote:
 future==0.9.0

It looks like that library is out of date.  The current version looks
to be 0.12.0, and it also looks like this bug was fixed in the 0.12.0
release.  I'd upgrade your version if at all possible.

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Re: The “does Python have variables?” debate

[Jerry Hill]

On Wed, May 7, 2014 at 2:18 AM, Marko Rauhamaa ma...@pacujo.net wrote:
 Ned Batchelder n...@nedbatchelder.com:

 Why is variable sacrosanct and can only be used to describe C
 semantics, but we're OK reusing class, int, and function?

 The Python language specification calls them variables; the terminology
 discussion should end there.

Personally, I found the idea that a python variable is a name + value
pairing to be useful when learning the language, especially when I was
struggling with the calling semantics (that is, the differences
between call-by-value, call-by-reference, and call-by-object).  I
think it's rather silly for someone to insist that python doesn't have
variables.  On the other hand, I think it can be useful to point out
that python variable aren't like C variables, and that thinking of
python variables as having two parts -- names and values -- really can
help people who are struggling to learn the language.  I know it
certainly helped me.

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Re: Joining centos 6.5 member Domain Controller to an existing Windows Domain

[Jerry Hill]

On Mon, May 5, 2014 at 11:18 AM, Joshua Knights
christcade...@yahoo.com.dmarc.invalid wrote:

 Here is my Issue and I think it may be a python path bug?

It's not a bug in Python.  It looks to me like a configuration problem.

I'm going to assume you have a good reason for bypassing your OS's
package management system.  In general, this is a bad idea, but since
this isn't a linux administration list, I'll leave it at that.

 Then I downloaded Samba with the following command:
 git clone git://git.samba.org/samba.git samba-master
 Then I installed the additional openldap-devel Library
 then I did the ./configure --enable-debug --enable-selftest
 then initiated the make command

So you configured it, and built it, but did not install it, right?
You didn't do a make install or make altinstall?  Installing would
presumably have put the files in the right place for them to be picked
up by python.  Since you just built samba without installing it, it
looks like you have to point python to the right place.

 When I do a find / - name samba.netcmd.main

 It pulls up: NOTHING!!

Right, that's not surprising.  samba.netcmd.main is a python package,
not a module, so it won't be named samba.netcmd.main.py or whatever
you were thinking.

 If I pull up : find / -name netcmd

 I get:

 /root/samba-master/python/samba/netcmd
 /root/samba-master/bin/python/samba/netcmd
 /root/samba-master/bin/default/python/samba/netcmd

 In my research somebody said: to export the PYTHONPATH and to change it to 
 the correct path of the netcmd command.

You'll want to add the directory up to the /python bit.  I'm not
sure which one of those three is really the right location for the
module you're looking for, but I would start by trying
'/root/samba-master/bin/python'.  From there, python should be able to
find the samba package.

 if I wanted to fix it permanently then to update my bash.rc file.

 In other words Tell my samba tool where to look, and this look is only 
 temporary till I close my terminal. Placing the command in the bash.rc file 
 will run this script every time I open my terminal. Well, I tried all 3 and 
 none of them worked.

This is not a good way to leave your system.  It's okay if you're just
testing the new samba build, but you really ought to install the
software, not just run it out of the build directory.  Best of all
would be to install a version that's actually been packaged up for
your OS using the CentOS packaging system.

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Re: Reference

[Jerry Hill]

On Mon, Mar 3, 2014 at 11:52 PM, Steven D'Aprano st...@pearwood.info wrote:
 If your intention is to treat None as a singleton sentinel, not as a
 value, then you ought to use is to signal that intention, rather than
 using == even if you know that there won't be any false positives.

In all of the years I've been on this list, I don't think I've seen
more than one or two cases of someone deliberately treating None as a
singleton sentinel.  In most cases, they're either checking the return
value from a function or using it as a default argument to a function
to force some default behavior when no parameter is passed.  I'm
pretty sure you're going to say that the latter use is exactly where
you should us 'is' instead of '=='.  Respectfully, I disagree.

For a beginning python user, identity checking is an attractive
nuisance. The only time most beginners should use it is when comparing
to None.  But, as soon as they are taught that there are two
comparison operators, I start to see 'is' cropping up in more and more
places where they ought to use '=='.  And the problem is that
sometimes it works for them, and sometimes it doesn't.  Sure, students
eventually need to understand the difference between identity and
equality.  My problem is that by enshrining in python custom that the
only correct way to compare to None is with 'is', we have to explain
that concept way early in the teaching process.  I can't count the
number of times that a thread has completely derailed into identity vs
equality, then into interning of strings and small integers, and
suddenly the thread is 40 messages long, and no one has actually
talked about the code that was originally posted beyond that issue.
In approximately zero cases, have I seen code where 'is' versus '=='
actually made any difference, except where the 'is' is wrong.  I've
also never seen the supposedly ever-present boogie man of an object
that mistakenly compares equal to None, much less seen that object
passed to functions with None-based sentinels.

I feel like 'is' is an operator that ought to be saved for an advanced course.

Out of curiosity, do you think we should be doing truth checking with
'is'?  True and False are singletons, and it seems to me that the
justification for idenity versus equality should be just as strong
there, but I don't think I've ever seen anyone even suggest that.

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Re: Reference

[Jerry Hill]

On Mon, Mar 3, 2014 at 4:51 PM, Tim Chase python.l...@tim.thechases.com wrote:
 There are a couple use-cases I've encountered where is matters:

 1) the most popular:

   if foo is None:
 do_stuff()

I know this is the one that always comes up, but honestly, I feel like
is doesn't matter here.  That code would be just as correct if it
was written as:

if foo == None:
do_stuff()

The only time it would give you a different result from the is
version is if foo was bound to an object that returned True when
compared with None.  And if that were the case, I'm still not
convinced that you can tell from looking at those two lines of code
which one is buggy, except for the fact that there has been 20 years
of custom saying that comparing to None with equality is wrong.

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Re: posting code snippets

[Jerry Hill]

On Thu, Feb 27, 2014 at 7:13 AM, Mark H. Harris harrismh...@gmail.com wrote:
 hi folks,
Its been too long... can't remember... are there rules here about posting 
 code snippets, or length considerations, and so forth?

Chris' advice about just posting your code inline with your message is
good.  If the problem is that you think your code is too long to post
inline, you're probably right.  That means it's probably also too long
for people to give it much attention.  If you really want people to
help figure out what is going on with code you don't understand, the
best thing to do is to post a Short, Self Contained, Correct Example
(http://www.sscce.org/).  That means cutting the code down to the bare
minimum required to demonstrate your issue.  Many times, the very act
of cutting the code down to a digestible chunk will show you the
problem without posting.  And if you still don't understand what's
going on, you're much more likely to get help when you present a
problem that can be read in a single screenful or so of code.

A related question, is there a python repository for uploading  py  files, 
 patches, suggestions, etc?

Assuming this goes beyond posting code for people on the list to look
at, yes, there are lots of places to post python code.

For short bits, Activestate has a repository of python recipes:
http://code.activestate.com/recipes/langs/python/

For publishing full modules and packages, there's the python package
index: https://pypi.python.org/pypi

Patches, bugs and feature requests for the python language itself
belong here: http://bugs.python.org/ attached to an appropriate
tracker issue.  Feature requests should probably be raised on the
python-ideas mailing list
(https://mail.python.org/mailman/listinfo/python-ideas) before opening
an issue on the bug tracker.

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Re: Win32 Write RAW Physical Disk Python 3.3.2

[Jerry Hill]

On Wed, Feb 19, 2014 at 7:42 AM, khanta kha...@gmail.com wrote:
 Hello,
  I am trying to write to the raw physical disk on Windows 8.1 but I
 get an error:
 PermissionError: [Errno 13] Permission denied: '.\\PHYSICALDRIVE2'

Is there a volume mounted from the drive at the time you're attempting
to write to the physical device?  According to some MSDN documentation
(http://msdn.microsoft.com/en-us/library/aa365747%28VS.85%29.aspx ),
it doesn't look like you can write to a physical device if the sectors
you're attempting to write are mounted at the time. There appear to be
a lot of caveats.  Take a look at the section of that page starting
with If you write directly to a volume that has a mounted file
system, you must first obtain exclusive access to the volume. for
lots of details.

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Re: Simple Object assignment giving me errors

[Jerry Hill]

On Wed, Feb 12, 2014 at 4:42 PM, Nir nircher...@gmail.com wrote:
 If this makes sense to you, great. I am trying to break it down so that I can 
 make sense of it. As you mentioned self[name] = filename doesn't work 
 unless I built a class to handle it. I guess my question then, is how is the 
 class handling it in this code? If you can show me by stripping it down to 
 the bare minimum or write an example that would be awesome.

This example works because the UserDict object being used in this code
was built to handle it.  The UserDict class in the standard library
does a lot more than the little snippet you had in your original code.
 Your original code would work if you did the same thing, like this:

from collections import UserDict

class FileInfo(UserDict):
def __init__(self, filename=None):
UserDict.__init__(self)
self[name] = filename


jeez = FileInfo(yo)

(If you're using Python 2, then the first line should be from
UserDict import UserDict instead).

You can take a look at the source code for the userDict class here:
http://hg.python.org/cpython/file/3.3/Lib/collections/__init__.py#l862
.  In that class, the code responsible for handling the bracketed name
lookup (i.e., self[name]), is in the __getitem__ and __setitem__
methods (and peripherally in __delitem__, __len__ and __contains__)

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Re: [OT] Usage of U+00B6 PILCROW SIGN (was: generator slides review and Python doc (+/- text bug))

[Jerry Hill]

On Tue, Feb 4, 2014 at 1:51 AM,  wxjmfa...@gmail.com wrote:
 I got it. If I'm visiting a page like this:

 http://docs.python.org/3/tutorial/index.html#the-python-tutorial

 1) To read the page, I'm scrolling down.
 2) When I have finished to read the page, I scroll up
 (or scroll back/up) to the top of the page until I see
 this feature and the title.
 3) I click on this feature.
 4) The title, already visible, moves, let's say, 2cm higher.

 ...?

Those links aren't for navigation.

They're so you can discover anchor links in the page and pass them to
someone else.  For instance, if I want to point someone to the section
of the tutorial that talks about reading and writing files, I could
just give them this link:
http://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files,
instead of pointing them to the main page and instructing them to
scroll down until they see Section 7.2

I was able to discover that link by opening the page, highlighting the
section header with my mouse, then clicking the pilcrow.  That gives
me the anchor link to that section header.
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Re: How to make a tkinter GUI work on top of a CUI program?

[Jerry Hill]

On Fri, Jan 3, 2014 at 9:44 PM, Beinan Li li.bei...@gmail.com wrote:
 But some console programs have their own shell or ncurse-like CUI, such as
 cscope.
 So I figured that I need to first subprocess.popen a bidirectional pipe and
 send command through stdin and get results from stdout and stderr.

 But in such a case I found that communicate('cmd') will freeze.

Right.  communicate() waits for the subprocess to end, and the
subprocess is still waiting for you to do something.  Instead, you'll
need to read() and write() to the subprocess' stdin and stdout
attributes, probably something like this (untested):

def OnClickBtn(self, event):
print('OnClickBtn')
self.subProc.stdin.write('symbolName\n')
print(self.subProc.stdout.read())

It looks like cscope has both a screen-oriented mode and a line-based
mode.  When you're working with a subprocess like this, you're going
to want to be in the line-based mode, so you'll probably want to add
-l or -L to your command line.

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Re: Copy a file like unix cp -a --reflink

[Jerry Hill]

On Wed, Dec 18, 2013 at 1:37 PM, Paulo da Silva
p_s_d_a_s_i_l_...@netcabo.pt wrote:
 Hi!

 Is there a way to copy a file the same as Unix command:

 cp -a --reflink src dest

 without invoking a shell command?

I started to dig through the cp man page to see what that did, then
gave up when each option expanded out to several more.  i.e., -a,
--archive same as -dR --preserve=all leads to looking up -d -R and
--preserve, etc.

To me, it's just not worth it to spend more time researching your
question than you spent writing the email asking it. If you don't get
the answers you're looking for, you might try asking again, specifying
the exact behavior you'd like to achieve.

PS: That isn't really meant as any kind of complaint about your
question.  It's consise, easy to read, and gets right to the point.
It just assumes a lot of background knowledge.  If someone else
happens to already know all of that background, they may be able to
help right off.  If not, they may be interested enough to do the
research to figure it all out and then help. You just may be able to
prompt more people to help by cutting down on the amount of work it
would take them to do so.

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Re: how to develop code using a mix of an existing python-program and console-commands

[Jerry Hill]

On Wed, Dec 18, 2013 at 3:17 PM, Jean Dubois jeandubois...@gmail.com wrote:
 I have a python-program which I want to perform its task first, then
 switch to
 the python console to experiment with further commands, using what was
 already
 defined in the python-program.
 I want this as an alternative for what I do now (but which is not very
 efficient):
 I start the python-console and then manually copy-paste line per line from
 the program in the console, then try out possible continuation commands,
 if however something goes wrong I have to redo the whole process.

On the command line, python itself can take command line options,
including one that does exactly what you're looking for.

python -i script.py

That command will run script.py to its end, then drop you into the
interactive interpreter with the environment intact from running the
script.

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Re: Why is there no natural syntax for accessing attributes with names not being valid identifiers?

[Jerry Hill]

On Wed, Dec 4, 2013 at 3:35 PM, Piotr Dobrogost
p...@google-groups-2013.dobrogost.net wrote:
 Right. If there's already a way to have attributes with these non-standard 
 names (which is a good thing) then for uniformity with dot access to 
 attributes with standard names there should be a variant of dot access 
 allowing to access these non-standard named attributes, too.

Given the follow code, what do you think should print?

class My_Class(object):
pass

bar = 1
my_object = My_Class()
setattr(my_object, 'foo', 10)
setattr(my_object, 'bar', 100)
setattr(my_object, 'foo-bar', 1000)

print(my_object.foo-bar)

Today (in python 3.3), it prints 9, because my_object.foo is 10, the
local variable bar is equal to 1, and 10 minus 1 is 9..  Under your
new proposal, it would print 1000, right?  Is there any way for your
proposal to be backwards compatible?

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Re: Python GUI?

[Jerry Hill]

On Wed, Sep 11, 2013 at 4:55 PM,  eamonn...@gmail.com wrote:
 Have you got anything to say on what one I should be using(excluding PyQT 
 because it has a DD designer :( )? Is Tkinter really dead? Should I stick 
 with wxPython?

If that's a reason for excluding a GUI toolkit, you're in trouble.
Drag and drop layout tools exist for all of your proposed systems.

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Re: subprocess.Popen instance hangs

[Jerry Hill]

On Fri, Aug 30, 2013 at 11:32 AM, Tim Johnson t...@akwebsoft.com wrote:
   The objective is to display all output, but to also separate error
   messages from normal output.

I still think you want to use communicate().  Like this:

p = subprocess.Popen(args,stderr=subprocess.PIPE,stdout=subprocess.PIPE)
output, err = p.communicate()

That's it.  No need for a loop, or manually handling the fact that
stderr and/or stdout could end up with a full buffer and start to
block.

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Re: PEPs should be included with the documentation download

[Jerry Hill]

On Wed, Aug 21, 2013 at 1:55 PM,  random...@fastmail.us wrote:
 I think, though, that if there's any useful information that can be
 obtained by reading accepted PEPs but not the documentation, or if
 things are explained less clearly than in the PEPs, that's a bug in the
 documentation, and should be remedied by adding to the documentation.

Personally, the only PEPs I've used as reference material as PEP 8
(the Python Style Guide), and PEP 249 (the Python Database API
Specification v2.0).  If I recall correctly, one of the database
adapters I used basically said that they were PEP 249 compliant, and
didn't have much documentation beyond that.

It seems to me that adding the PEPs to the compiled documentation
would be a good thing.  They are at least as useful as the Language
Reference or the Embedding and Extending Python sections that are
already included.

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Re: PyGLet, 2to3...?

[Jerry Hill]

On Thu, Jul 25, 2013 at 7:49 PM, John Ladasky
john_lada...@sbcglobal.net wrote:
 ===

 john@john:~/Desktop/pyglet-1.2alpha1$ sudo python3 setup.py install

 [sudo] password for john:

 running install
 running build
 running build_py
 running install_lib
 running install_egg_info
 Removing /usr/local/lib/python3.3/dist-packages/pyglet-1.2alpha1.egg-info
 Writing /usr/local/lib/python3.3/dist-packages/pyglet-1.2alpha1.egg-info

Pyglet was installed to /usr/local/lib/python3.3/dist-packages ...

 john@john:~/Desktop/pyglet-1.2alpha1$ python3

 Python 3.3.1 (default, Apr 17 2013, 22:30:32)
 [GCC 4.7.3] on linux
 Type help, copyright, credits or license for more information.
 import pyglet
 Traceback (most recent call last):
   File stdin, line 1, in module
   File ./pyglet/__init__.py, line 276
 print '[%d] %s%s %s' % (thread, indent, name, location)
^
 SyntaxError: invalid syntax

... But here, the error message is talking about ./pyglet/__init__.py.
 I think you're accidentally importing the pyglet package from the
local directory instead of from the proper location in dist-packages.
Try changing back to your home directory and trying this again.  I
think you're picking up the code from
~/Desktop/pyglet-1.2alpha1/pyglet instead of from
/usr/local/lib/python3.3/dist-packages.

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Re: Geo Location extracted from visitors ip address

[Jerry Hill]

On Fri, Jul 5, 2013 at 3:08 PM, Νίκος Gr33k ni...@superhost.gr wrote:
 Is there a way to extract out of some environmental variable the Geo
 location of the user being the city the user visits out website from?

 Perhaps by utilizing his originated ip address?

No, you'd need to take the originating IP address and look it up in a
geolocation database or submit it to a geolocation service and get the
response back from them.  It's not stored in any environment
variables.

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Re: detect key conflict in a JSON file

[Jerry Hill]

On Wed, May 29, 2013 at 1:10 PM, Chris Rebert c...@rebertia.com wrote:

 On Wed, May 29, 2013 at 4:16 AM, Jabba Laci jabba.l...@gmail.com wrote:
  I have a growing JSON file that I edit manually and it might happen
  that I repeat a key. If this happens, I would like to get notified.
  Currently the value of the second key silently overwrites the value of
  the first.

 You can pass an appropriate object_pairs_hook function to json.load():
 http://docs.python.org/2/library/json.html#repeated-names-within-an-object
 http://docs.python.org/2/library/json.html#json.load


​That makes it pretty easy to provide any validation you might like to your
JSON data. Here's a quick example that raises ValueError on duplicate keys,
since the docs didn't have any examples.

Python 3.2.2 (default, Sep  4 2011, 09:51:08) [MSC v.1500 32 bit (Intel)]
on win32

​ s = '{x: 1, x: 2, x: 3}'
 def json_checker(seq):
d = {}
for key, value in seq:
if key in d:
raise ValueError(Duplicate key %r in json document % key)
else:
d[key]=value
return d

 json.loads(s, object_pairs_hook=json_checker)
Traceback (most recent call last):
  File pyshell#31, line 1, in module
json.loads(s, object_pairs_hook=checker)
  File C:\Python32\lib\json\__init__.py, line 320, in loads
return cls(**kw).decode(s)
  File C:\Python32\lib\json\decoder.py, line 351, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File C:\Python32\lib\json\decoder.py, line 367, in raw_decode
obj, end = self.scan_once(s, idx)
  File pyshell#30, line 5, in json_checker
raise ValueError(Duplicate key %r in json document % key)
ValueError: Duplicate key 'x' in json document

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Re: PEP 378: Format Specifier for Thousands Separator

[Jerry Hill]

On Thu, May 23, 2013 at 6:20 PM, Carlos Nepomuceno 
carlosnepomuc...@outlook.com wrote:

 Can str.format() do the following?

 f = '%d %d %d'
 v = '1,2,3'
 print f % eval(v)


​Sure:

Python 3.2.2 (default, Sep  4 2011, 09:51:08) [MSC v.1500 32 bit (Intel)]
on win32
 f = {} {} {}
 v = 1,2,3
 print(f.format(*eval(v)))
1 2 3


The * unpacks the tuple returned from eval(), so that you get 3 separate
parameters passed to format(), instead of the single tuple.​

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​
Jerry​
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Re: python backup script

[Jerry Hill]

On Mon, May 6, 2013 at 3:01 PM, MMZ programmer.toro...@gmail.com wrote:

 I am trying to backup database on CentOS linux server,I'm getting error
 when running the following script. anyone can help?

 Traceback (most recent call last):
   File ./backup.py, line 8, in ?
 username = config.get('client', 'mmz')
   File /usr/lib/python2.4/ConfigParser.py, line 511, in get
 raise NoSectionError(section)


​I've never used ConfigParser, but that ​

​error message looks pretty simple to interpret.  You've set up a
ConfigParser object, told it to read in ~/my.cnf, the asked for the value
of section 'client', option 'mmz'.  The error indicates that your config
files doesn't have a section named 'client'.

What is the content of your ~/my.cnf file?

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Re: import in Python3.3

[Jerry Hill]

On Mon, Mar 25, 2013 at 11:49 PM, rocky ro...@gnu.org wrote:
 On Sun, 24 Mar 2013 18:12:49 -0500, Fabian von Romberg wrote:
  I have a package name collections and inside of my package I want to

 I find this kind of thing sad: it feels to me that programmers are working 
 around somewhat arbitrary and changing restrictions. Rather than avoid names 
 like collections, why not try to address the underlying problem? There 
 isn't an ambiguity here in my view: the fullname is mypackage.collections

You've said a couple of times now that the original author has a
package named mypackage with a module collections in it.  As far
as I can tell, that's untrue.  The original post claims to have a
package named collections, which is colliding with the builtin
module of the same name.

As far as I can tell, all of your suggestions about using your
pyimport-relative tool aren't helpful unless the author re-names his
package from collections to mypackage and then moves all of their
code into a collections module inside mypackage, right?

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Re: Maximum Likelihood Estimation

[Jerry Hill]

On Fri, Feb 1, 2013 at 1:59 PM, Michael Torrie torr...@gmail.com wrote:
 Most people on this list consider 8 dihedral to be a badly
 programmed bot.

For what it's worth, I think it's a very cleverly programmed bot.  It
usually makes just enough sense for me to wonder if there really is a
human being behind the keyboard.

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Re: Else statement executing when it shouldnt

[Jerry Hill]

On Wed, Jan 23, 2013 at 8:35 AM, Jussi Piitulainen
jpiit...@ling.helsinki.fi wrote:
 The feature isn't bad, it's just very, very badly named.

 I believe it would read better - much better - if it was for/then
 and while/then instead of for/else and while/else.

That's always been my opinion too.  I'd remember how the construct
worked if it was for/then (and while/then).  Since seeing for/else
always makes my brain lock up for a few seconds when I'm reading code,
I don't bother using it.

Jerry
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Re: Python parser problem

[Jerry Hill]

On Wed, Dec 12, 2012 at 2:10 PM, RCU alex.e.s...@gmail.com wrote:
 With this occasion I would like to ask also what are the limits of the
 Python 2.x and 3.x parser. Where can I find what are the limits on the
 size/lines of the parsed script?

The Python Language Reference is probably what you're looking for:
http://docs.python.org/2/reference/index.html

See, particularly, section 2 about lexical analysis and possibly
section 9 for the grammar.  The short answer though, is that python
doesn't have any limits on the line length or the size of a script,
other than that execution will obviously fail if you run out of memory
while parsing or compiling the script.

PEP 8 (http://www.python.org/dev/peps/pep-0008/) is the Python style
guide, and it does have some recommendations about line length
(http://www.python.org/dev/peps/pep-0008/#maximum-line-length).  That
document suggests a maximum length of 79 characters per line, and
that's probably what PythonTidy was trying to accomplish by splitting
your line.

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Re: problem with usbtmc-communication

[Jerry Hill]

On Tue, Dec 11, 2012 at 1:58 AM, Jean Dubois jeandubois...@gmail.com wrote:

 I found examples in the usbtmc kernel driver documentation (the
 examples there are given in C):
 http://www.home.agilent.com/upload/cmc_upload/All/usbtmc.htm?cc=BElc=dut

Thanks for that link.  I think it explains how the driver works pretty
well.  I haven't done any work with devices like this, but I see a few
things in those docs that might help.

In their example code, they open the device with: open(“/dev/usbtmc1”,O_RDWR);

That's not exactly the same as what you've been doing.  I would try
opening the file this way in python:
usb_device = open('/dev/usbtmc1', 'w+', buffering=0)

That truncates the file after it opening it, and disables any
buffering that might be going on.

Then, I would try writing to the device with usb_device.write() and
usb_device.read().  read() attempts to read to end-of-file, and based
on the docs, the driver will work okay that way.  Doing that, along
with turning off buffering when you open the file, should eliminate
any issues with the driver failing to emit newlines someplace.

Personally, I would probably try playing with the device from python's
interactive interpreter.  I think that could shed a lot of light on
the behavior you're seeing.

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Re: string contains and special characters

[Jerry Hill]

On Tue, Oct 9, 2012 at 10:02 AM, loial jldunn2...@gmail.com wrote:
 I am trying to match a string that containing the  and  characters, 
 using the string contains function, but it never seems to find the lines 
 containing the string

 e.g if mystring.contains(TAG) :

 Do I need to escape the characters...and if so how?

Strings don't have a contains() method.  Assuming that mystring is
actually a string, you should be getting a very specific error,
telling you exactly what's wrong with your code (something like
AttributeError: 'str' object has no attribute 'contains').

If that isn't what you're seeing, you'll need to provide the full and
complete text of the error you are getting, and preferably enough of
your code that we can reproduce the issue and help you solve it.

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Re: get google scholar using python

[Jerry Hill]

On Mon, Oct 1, 2012 at 1:28 PM, রুদ্র ব্যাণার্জী bnrj.ru...@gmail.com wrote:
 So, If I manage to use the User-Agent as shown by you, will I still
 violating the google EULA?

Very likely, yes.  The overall Google Terms of Services
(http://www.google.com/intl/en/policies/terms/) say Don’t misuse our
Services. For example, don’t interfere with our Services or try to
access them using a method other than the interface and the
instructions that we provide.

The only method that Google appears to allow for accessing Scholar is
via the web interface, and they explicitly block web scraping through
that interface, as you discovered.  It's true that you can get around
their block, but I believe that doing so violates the terms of
service.

Google does not appear to offer an API to access Scholar
programatically, nor do I see a more specific EULA or TOS for the
Scholar service beyond that general TOS document.

That said, I am not a lawyer.  If you want legal advice, you'll need
to pay a lawyer for that advice.

-- 
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Re: Python source code easy to hack?

[Jerry Hill]

On Fri, Sep 28, 2012 at 10:18 AM,  stu...@molden.no wrote:
 Python bytecode is not easier to hack than Java or .NET bytecodes.

This is true, but both java and .net are also relatively easy to decompile.

In general though, why does it matter?  What are you trying to protect
yourself against?  If you're including secrets in your code like
encryption keys or bank account numbers, there's no way to keep them
out of the hands of a determined attacker that has access to your
file, no matter what language it may be written in.

If you must keep anyone from ever seeing how your code works, the only
way to do that is to keep all the sensitive bits running on a machine
that you control.  Typically, you would do that by distributing a
client portion of your application, and also running a web service.
Then you can have your client connect to the web service, request that
the sensitive calculations, or money transfer, or whatever, be done on
the server, and just pass back the results.

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Re: How to limit CPU usage in Python

[Jerry Hill]

On Thu, Sep 27, 2012 at 12:58 PM, Prasad, Ramit
ramit.pra...@jpmorgan.com wrote:
 On *nix you should just set the appropriate nice-ness and then
 let the OS handle CPU scheduling. Not sure what you would do
 for Windows--I assume OS X is the same as *nix for this context.

On windows, you can also set the priority of a process, though it's a
little different from the *nix niceness level.  See
http://code.activestate.com/recipes/496767/ for a recipe using
pywin32.  I believe the psutil module handles this too, but I don't
think it manages to abstract away the platform differences.

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

[Jerry Hill]

On Fri, Sep 21, 2012 at 9:31 AM, BobAalsma overhaalsgang_24_...@me.com wrote:
 Thanks, Joel, yes, but as far as I'm aware these would all require the Python 
 programme to have the user's username and password (or credentials), which 
 I wanted to avoid.

No matter what you do, your web service is going to have to
authenticate with the remote web site.  The details of that
authentication are going to vary with each remote web site you want to
connect to.

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Re: How to limit CPU usage in Python

[Jerry Hill]

On Thu, Sep 20, 2012 at 11:12 AM, Rolando Cañer Roblejo
rolando.ca...@cnic.edu.cu wrote:
 Hi all,

 Is it possible for me to put a limit in the amount of processor usage (%
 CPU) that my current python script is using? Is there any module useful for
 this task? I saw Resource module but I think it is not the module I am
 looking for. Some people recommend to use nice and cpulimit unix tools, but
 those are external to python and I prefer a python solution. I am working
 with Linux (Ubuntu 10.04).

Maximum percentage of CPU used isn't normally something you control.
The only way I know of to do it involves having another process
monitor the thing you want to control and sending signals to stop and
start it (e.g., http://cpulimit.sourceforge.net/).

Typically, you instead want to control the priority (so that higher
priority apps can easily take more CPU time).  That's what nice is for
(http://docs.python.org/library/os.html#os.nice).  If you want to
limit a process in the same way that ulimit does, then the resources
module is what you want
(http://docs.python.org/library/resource.html#resource.setrlimit).

Is there a particular reason that you'd rather have your CPU sitting
idle, rather than continuing with whatever code is waiting to be run?
I'm having a hard time understanding what problem you might be having
that some combination of setting the nice level and imposing resource
limits won't handle.

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Re: Accessing dll

[Jerry Hill]

On Thu, Sep 6, 2012 at 11:07 AM, Helpful person rrl...@yahoo.com wrote:
 I am a complete novice to Python.  I wish to access a dll that has
 been written to be compatible with C and VB6.  I have been told that
 after running Python I should enter  from ctypes import * which
 allows Python to recognize the dll structure.  I have placed the dll
 into my active directory (if that's the correct word, one on my path)
 for simplification.

 I tried:   import name.dll but this just gave me an error telling me
 that there was no such module.

 Can someone please help?

You should start by reading the ctypes documentation, here:
http://docs.python.org/library/ctypes.html .  It has a lot of examples
that ought to get you started.

When you run into more specific problems, you're going to have to
provide a lot more information before we can help you, including the
specific documentation of the DLL you're trying to wrap, your
platform, and python version.  If you are not permitted to share those
things, we may not be able to give you much help.  Ctypes is very
specific to the actual library you are accessing, and requires that
you understand the requirements of the underlying DLL.

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Re: Accessing dll

[Jerry Hill]

On Thu, Sep 6, 2012 at 12:46 PM, Helpful person rrl...@yahoo.com wrote:
 The reference might help if I could get Python to recognize the dll as
 a module.

That's never going to happen.  It's a DLL, not a python module.  I
think the documentation lays that out pretty explicitly.  Have you
experimented with the very first bit of example code in the
documentation?  What do you get if you do the following at the
interactive interpreter?

 from ctypes import *
 print windll.insert your dll name here, without the .dll extension


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Re: Objects in Python

[Jerry Hill]

On Thu, Aug 23, 2012 at 4:59 AM, Jussi Piitulainen
jpiit...@ling.helsinki.fi wrote:
 I don't get it either. To me the python-has-no-variables campaigners
 seem confused. As far as I can see, Python can be seen in terms of
 variables bound to (locations containing) values perfectly well, in a
 way that should be quite familiar to people who come from Java (or
 Lisp, Scheme like me).

Personally, when I was learning python I found the idea of python
having names and values (rather than variables and references) to
clear up a lot of my misconceptions of the python object model.  I
think it's done the same for other people too, especially those who
come from the C world, where a variable is a named and typed location
in memory.

Perhaps those that come from the Java and Lisp world don't find the
name/value paradigm as helpful.  Still, it seems silly to excoriate
people on the list for trying to explain python fundamentals in
several different ways.  Sometimes explaining the same idea in
different words helps people understand the concept better.

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Re: writelines puzzle

[Jerry Hill]

On Wed, Aug 22, 2012 at 11:38 AM, William R. Wing (Bill Wing)
w...@mac.com wrote:
 Much to my surprise, when I looked at the output file, it only contained 160 
 characters.  Catting produces:

 StraylightPro:Logs wrw$ cat RTT_monitor.dat
 2354[ 734716.72185185  734716.72233796  734716.72445602 ...,  734737.4440162
   734737.45097222  734737.45766204][ 240.28.5   73.3 ...,   28.4   27.4   
 26.4]

If that's the full output, then my guess is that x_dates and y_rtt are
not actual python lists.  I bet they are, in fact, numpy arrays and
that the string representation of those arrays (what you're getting
from str(x_dates), etc) include the '...' in the middle instead of the
full contents.

Am I close?

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Re: python 6 compilation failure on RHEL

[Jerry Hill]

On Tue, Aug 21, 2012 at 12:34 AM, John Nagle na...@animats.com wrote:
 After a thread of clueless replies, it's clear that nobody
 responding actually read the build log.  Here's the problem:

The very first reply, Emile's, pointed out that these were optional
modules, and that python did, in fact build successfully.

   Failed to find the necessary bits to build these modules:
 bsddb185
 dl
 imageop
 sunaudiodev

 What's wrong is that the Python 2.6 build script is looking for
 some antiquated packages that aren't in a current RHEL.  Those
 need to be turned off.

They don't need to be turned off.  They can either be ignored (because
they aren't needed, and did not cause the build to fail), or the
development libraries for those pieces can be installed and python
recompiled.

The rest of the thread has been commenting on the OP's choice of
python version and operating system.  That's not exactly on topic, but
the original question was answered in the very first response.

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Re: ONLINE SERVER TO STORE AND RUN PYTHON SCRIPTS

[Jerry Hill]

On Sun, Aug 19, 2012 at 6:27 PM, coldfire amangill.coldf...@gmail.com wrote:
 Also I have no idea how to deploy a python script online.
 I have done that on my local PC using Apache server and cgi but it Works fine.
 Whats this all called? as far as I have searched its Web Framework but I dont 
 wont to develop  a website Just a Server which can run my scripts at specific 
 time and send me email if an error occurs.
 I use Python And i am not getting any lead.

If you want to host web pages, like your're doing on your local pc
with Apache and cgi, then you need an account with a web server, and a
way to deploy your scripts and other content.  This is often known as
a 'web hosting service'[1].  The exact capabilities and restrictions
will vary from provider to provider.

If you just want an alway-on, internet accessable place to store and
run your python scripts, you may be interested in a 'shell
account'[2], or if you need more control over the environment, a
'virtual private server'[3].

That may give you a few terms to google, and see what kind of service you need.

1 http://en.wikipedia.org/wiki/Shell_account
2 http://en.wikipedia.org/wiki/Web_host
3 http://en.wikipedia.org/wiki/Virtual_private_server

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Re: Why doesn't Python remember the initial directory?

[Jerry Hill]

On Sun, Aug 19, 2012 at 9:57 PM, kj no.em...@please.post wrote:
 By now I have learned to expect that 99.99% of Python programmers
 will find that there's nothing wrong with behavior like the one
 described above, that it is in fact exactly As It Should Be, because,
 you see, since Python is the epitome of perfection, it follows
 inexorably that any flaw or shortcoming one may *perceive* in Python
 is only an *illusion*: the flaw or shortcoming is really in the
 benighted programmer, for having stupid ideas about programming
 (i.e. any idea that may entail that Python is not *gasp* perfect).
 Pardon my cynicism, but the general vibe from the replies I've
 gotten to my post (i.e. if Python ain't got it, it means you don't
 need it) is entirely in line with these expectations.

Since you have no respect for the people you're writing to, why
bother?  I know I certainly have no desire to spend any time at all on
your problem when you say things like that.  Perhaps you're looking
for for the argument clinic instead?

http://www.youtube.com/watch?v=RDjCqjzbvJY

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Re: How do I display unicode value stored in a string variable using ord()

[Jerry Hill]

On Fri, Aug 17, 2012 at 1:49 PM,  wxjmfa...@gmail.com wrote:
 The character '…', Unicode name 'HORIZONTAL ELLIPSIS',
 is one of these characters existing in the cp1252, mac-roman
 coding schemes and not in iso-8859-1 (latin-1) and obviously
 not in ascii. It causes Py3.3 to work a few 100% slower
 than Py3.3 versions due to the flexible string representation
 (ascii/latin-1/ucs-2/ucs-4) (I found cases up to 1000%).

 '…'.encode('cp1252')
 b'\x85'
 '…'.encode('mac-roman')
 b'\xc9'
 '…'.encode('iso-8859-1') # latin-1
 Traceback (most recent call last):
   File eta last command, line 1, in module
 UnicodeEncodeError: 'latin-1' codec can't encode character '\u2026'
 in position 0: ordinal not in range(256)

 If one could neglect this (typographically important) glyph, what
 to say about the characters of the European scripts (languages)
 present in cp1252 or in mac-roman but not in latin-1 (eg. the
 French script/language)?

So... python should change the longstanding definition of the latin-1
character set?  This isn't some sort of python limitation, it's just
the reality of legacy encodings that actually exist in the real world.


 Very nice. Python 2 was built for ascii user, now Python 3 is
 *optimized* for, let say, ascii user!

 The future is bright for Python. French users are better
 served with Apple or MS products, simply because these
 corporates know you can not write French with iso-8859-1.

 PS When TeX moved from the ascii encoding to iso-8859-1
 and the so called Cork encoding, they know this and provided
 all the complementary packages to circumvent this. It was
 in 199? (Python was not even born).

 Ditto for the foundries (Adobe, Linotype, ...)


I don't understand what any of this has to do with Python.  Just
output your text in UTF-8 like any civilized person in the 21st
century, and none of that is a problem at all.  Python make that easy.
 It also makes it easy to interoperate with older encodings if you
have to.

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Re: print(....,file=sys.stderr) buffered?

[Jerry Hill]

On Mon, Aug 13, 2012 at 11:16 AM, Helmut Jarausch jarau...@skynet.be wrote:
 Now, when executing this, I always get

 +++ before calling foo
 --- after  calling foo
 entering foo ...

Can you give us a piece of code we can run that produces this output
for you?  You gave us an outline in your original post, but it would
be useful to have a self contained example that you can say reliably
produces the unexpected output for you.

Also, what environment, OS, and exact python version is this?  Is the
code being run in an IDE of some sort?  Does the behavior change if
you call your code directly from the command line?

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Re: howto do a robust simple cross platform beep

[Jerry Hill]

On Fri, Jul 13, 2012 at 9:00 PM, Gelonida N gelon...@gmail.com wrote:
 I tried the simplest approach (just printing the BEL character '\a' chr(7)
 to the console.

That's what I do when I want to send an audible alert to the user of a
console based program.  It's then up to the user's terminal to do
whatever the user wants. Printing a BEL character has the added
advantage that it plays nicely with programs that are run remotely
(through ssh sessions and the like).

Personally, I'm usually in a screen session, inside either an xterm or
over an ssh link, and have visual bells turned on so I can see the
alerts, even when they pop up in another screen.

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Re: using identifiers before they are defined

[Jerry Hill]

On Tue, Jun 12, 2012 at 2:33 PM, Julio Sergio julioser...@gmail.com wrote:
 Suppose I have to define two functions, aa, and, bb that are designed to call
 each other:

  def aa():
     ...
     ... a call of bb() somewhere in the body of aa
     ...

  def bb():
     ...
     ... a call of aa() somewhere in the body of bb
     ...


 Whatever the order of definition of aa and bb the problem remains, one of the
 two identifiers is not known ...

This works just fine in python, exactly as you've written it.  What's
the actual problem you're having?

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Re: English version for Mémento Python 3 (draft, readers needed)

[Jerry Hill]

On Wed, Jun 6, 2012 at 4:10 PM, Alec Ross a...@arlross.demon.co.uk wrote:
 FWIW, English idiomatic usage includes see overleaf, and see over, for
 the obverse side of a page/sheet, i.e, the following page; and see facing
 page, w/ the obvious meaning.

For what it's worth, I've never seen either of those constructs (see
overleaf and see over).  Are they perhaps more common in a
particular academic context, or possibly more common in places that
use British English spellings rather than American English?
Typically I've just seen see other side, or (very occasionally) see
reverse and see obverse.

Jerry
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Re: DateTime objectFormatting

[Jerry Hill]

On Wed, May 2, 2012 at 10:49 AM, Nikhil Verma varma.nikhi...@gmail.com wrote:
 What i am able to achieve with this class object to return is :-

 Gen GI Monday  May 7

 I want that the this class should return object like this :-

 Gen GI Monday AM, May 7
 Pancreas Tuesday PM, May 8

Check the documentation for the strftime method:
http://docs.python.org/library/datetime.html#strftime-and-strptime-behavior
 That has a list of the various formatting directives that can be used
to lay out your date and time as you wish.

In this case, instead of %A %B %d, you probably want %A %p, %B %d.
 That is, Full Weekday Name, followed by the AM/PM marker, then a
comma, then the Full Month Name and the day of month.

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Re: syntax for code blocks

[Jerry Hill]

On Tue, May 1, 2012 at 1:07 PM, Kiuhnm
kiuhnm03.4t.yahoo...@mail.python.org wrote:
 If you had read the module's docstring you would know that the public
 version uses

Are you aware that you've never posted a link to your module, nor it's
docstrings?  Are you also aware that your module is essentially
unfindable on google?  Certainly nothing on the first two pages of
google results for 'python codeblocks' jumps out at me as a python
module of that name.

Perhaps you would have better luck if you either post the actual code
you want people to critique, or posted a link to that code.

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Re: md5 check

[Jerry Hill]

On Wed, Apr 18, 2012 at 9:31 PM, contro opinion contropin...@gmail.com wrote:
 i have download  file (gpg4win-2.1.0.exe  from
 http://www.gpg4win.org/download.html)
 when i run :

 Type help, copyright, credits or license for
 import md5
 f=open('c:\gpg4win-2.1.0.exe','r')
 print md5.new(f.read()).hexdigest()
 'd41d8cd98f00b204e9800998ecf8427e'

 it is not  =  f619313cb42241d6837d20d24a814b81a1fe7f6d gpg4win-2.1.0.exe
 please see   :gpg4win-2.1.0.exe  from  http://www.gpg4win.org/download.html

 why ?

Probably because you opened the file in text mode, instead of binary
mode.  Try opening the file this way:

 f=open('c:\gpg4win-2.1.0.exe','rb')

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Re: Python Script Works Locally But Not Remotely with SSH

[Jerry Hill]

On Sat, Apr 7, 2012 at 5:41 PM, Dennis Lee Bieber wlfr...@ix.netcom.com wrote:
        The WinXP machine would need to have X-client translator (something
 that redirects all the Windows native graphics into X protocol and ships
 it to the specified server machine).

        As I recall -- such are not cheap applications.

X Servers for windows aren't expensive pieces of software anymore.
XMing is quite good, and free.  Cygwin also has an X server, but
Cygwin always seems like too much of a hassle to me.

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Re: Python Script Works Locally But Not Remotely with SSH

[Jerry Hill]

On Tue, Mar 27, 2012 at 8:51 PM, goldtech goldt...@worldpost.com wrote:
 I have a WinXP PC running an SSH server and I have a Linux PC with an
 SSH client  and logged into the XP seemingly OK. It's all on my
 personal LAN, the connection seems OK.

 I have a py file on the XP that I run via SSH from the Linux, it's:

 import webbrowser
 webbrowser.open('www.google.com')

 This runs OK started on the local XP PC, the browser Firefox opens and
 goes to the site, or it opens a tab to the site. But executing that
 same file via SSH does not open Firefox...doing it via SSH starts
 Firefox ( I see it begin in the process manager and I see web
 activity) but Firefox does not open it's window.

 Why the does the window not open when the script is started remotely?

How are you running the ssh server on the windows machine?  Is it a
windows service?  If so, what user does it run as, and is the service
configured to be allowed to interact with the desktop?

IIRC, by default most windows services run as a different user than
you, and do not have permission to interact with your desktop session.
 You may be able to get the firefox window to pop up on the ssh server
machine if you allow it to interact with the desktop, assuming that's
what you're trying to do.

Jerry
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Re: Python simulate browser activity

[Jerry Hill]

On Thu, Mar 15, 2012 at 10:54 PM, Chris Rebert c...@rebertia.com wrote:
 On Thu, Mar 15, 2012 at 7:23 PM, choi2k rex.0...@gmail.com wrote:
 The application aims to simulate user activity including visit a
 website and perform some interactive actions (click on the menu,
 submit a form, redirect to another pages...etc)

 Did you look at Selenium?
 http://seleniumhq.org/

You might also be interested in Sikuli (http://sikuli.org/), which
uses Jython to write scripts to automate other programs using
screenshots.  It's pretty neat if you need to automate a GUI that is
otherwise difficult to deal with.

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Re: GUI for pickle read

[Jerry Hill]

On Tue, Feb 28, 2012 at 12:51 PM, Smiley 4321 ssmil...@gmail.com wrote:
 Can I have some thoughts about - building a GUI to display the results of
 the pickle read?

 A prototype code should be fine on Linux.

It doesn't seem like it would be all that useful, though I may just be
lacking in imagination.  What would you do with such a thing?

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Re: Just curious: why is /usr/bin/python not a symlink?

[Jerry Hill]

On Thu, Feb 23, 2012 at 2:11 PM, HoneyMonster someone@someplace.invalid wrote:
 $ cd /usr/bin
 $ ls -l python*
 -rwxr-xr-x 2 root root 9496 Oct 27 02:42 python
 lrwxrwxrwx 1 root root    6 Oct 29 19:34 python2 - python
 -rwxr-xr-x 2 root root 9496 Oct 27 02:42 python2.7
 $ diff -s  python python2.7
 Files python and python2.7 are identical
 $

 I'm just curious: Why two identical files rather than a symlink?

It's not two files, it's a hardlink.  You can confirm by running ls
-li python* and comparing the inode numbers.

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Re: Just curious: why is /usr/bin/python not a symlink?

[Jerry Hill]

On Thu, Feb 23, 2012 at 2:34 PM, HoneyMonster someone@someplace.invalid wrote:
 On Thu, 23 Feb 2012 14:24:23 -0500, Jerry Hill wrote:
 It's not two files, it's a hardlink.  You can confirm by running ls -li
 python* and comparing the inode numbers.

 You are spot on. Thank you, and sorry for my stupidity.

I don't think you're stupid.  It's hard to tell the difference between
two separate files with the same file size and a hardlink.  The
biggest clue is the number 2 in the second column.  If I recall
correctly, for directories, that's the number of entries in the
directory.  For files, that number is the number of hardlinks
referring to that file.

Even with that, it's hard to tell what files are hardlinked together,
and figuring it out by inode is a pain in the neck.  Personally, I
prefer symlinks, even if they introduce a small performance hit.
Readability counts, even in the filesystem.

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Re: package extension problem

[Jerry Hill]

On Sun, Feb 12, 2012 at 1:46 PM, Fabrizio Pollastri f.pollas...@inrim.itwrote:

 Hello,

 I wish to extend the functionality of an existing python package by
 creating
 a new package that redefines the relevant classes of the old package. Each
 new class inherits the equivalent old class and adds new methods.
 ...

There is a way to solve this problem without redefining in the new package
 all the
 methods of the old package that return old classes?


The general answer is no.  If you want the methods of your subclass to
behave differently, in any way, from the same methods in the superclass,
then you must write new code that defines the behavior that you want.

Sometimes people write their classes so they automatically play nicely when
subclassed, and sometimes they don't.  In general, it's impossible to
always do the right thing when you don't know what particular behavior a
subclass might need to override, so a lot of times people don't bother to
write their classes to check for subclasses being passed in, etc.

Since you haven't actually shown us any code, that's about all I can tell
you.

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Re: object aware of others

[Jerry Hill]

On Sun, Jan 29, 2012 at 1:47 AM, Lee lchapli...@gmail.com wrote:

 I was afraid that a list/set/dictionary and alike is the answer, but,
 anyway, thanks everybody.


It doesn't seem too bad to keep track of the instances in the class object
using weak references (http://docs.python.org/py3k/library/weakref.html).
Here's an example that seems to do what you're asking using python 3.2, but
it should be pretty similar in python 2:

import weakref

class A:
_instances = set()
def __init__(self):
self.myname = 'IamA'
print('This is A')
self.__class__._instances.add(weakref.ref(self))
def foo(self):
print(foo)
def update(self):
for ref in self.__class__._instances:
obj = ref()
if obj is not None:
print(The only friends I've got are , ref, obj.myname)


If you're creating lots of instances of A and deleting them, it would
probably be worth removing the old weakrefs from the _instances set instead
of just ignoring them when calling update().

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Re: search google with python

[Jerry Hill]

On Wed, Jan 25, 2012 at 5:36 AM, Tracubik affdfsdfds...@b.com wrote:
 thanks a lot but it say it's deprecated, is there a replacement? Anyway
 it'll useful for me to study json, thanks :)

I don't believe Google is particularly supportive of allowing
third-parties (like us) to use their search infrastructure.  All of
the search-related APIs they used to provide are slowly going away and
not being replaced, as far as I can tell.

If you just need to search images (and not Google Image Search in
particular), Bing's API appears to be supported and not about to go
away.  ( http://msdn.microsoft.com/en-us/library/dd900818.aspx )

You could, in theory, make requests to Google just like a web browser
and parse the resulting HTML, but that tends to be fragile and prone
to break.  I believe it also violates Google's Terms of Service.

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Re: windows and home path

[Jerry Hill]

On Tue, Jan 24, 2012 at 9:56 AM, Andrea Crotti
andrea.crott...@gmail.com wrote:
 Window never stops to surprise me, I've been banging my head since yesterday
 and only
 now I now what is the problem.

 So suppose I have something like

 from os import path
 print path.expanduser('~')

 If I run it from cmd.exe I get /Users/user, doing the same in an emacs
 eshell buffer I get
 /Users/user/AppData/Roaming.

 What sense does it make??
 Is there a way to get always the same variable from python somehow?

The os.path.exanduser() docs (
http://docs.python.org/library/os.path.html#os.path.expanduser ) say
that On Windows, HOME and USERPROFILE will be used if set, otherwise
a combination of HOMEPATH and HOMEDRIVE will be used. An initial ~user
is handled by stripping the last directory component from the created
user path derived above.

So, my guess is that emacs is mangling your HOME environment variable.
 That appears to be confirmed by the emacs documentation here:
http://www.gnu.org/software/emacs/manual/html_node/emacs/General-Variables.html#General-Variables
.

At a guess, you do not have a system-wide HOME environment variable.
When you launch python from the command line, it uses either your
USERPROFILE setting, or is falling back to using HOMEDIRVE and
HOMEPATH.  When you launch emacs, it sees that HOME is not set, and
emacs helpfully sets it for you, to whatever path it thinks is
correct.  That would explain why you see different answers in
different environments.

Does that explain the behavior you're seeing?

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Re: windows and home path

[Jerry Hill]

On Tue, Jan 24, 2012 at 11:05 AM, Jerry Hill malaclyp...@gmail.com wrote:
 So, my guess is that emacs is mangling your HOME environment variable.
  That appears to be confirmed by the emacs documentation here:
 http://www.gnu.org/software/emacs/manual/html_node/emacs/General-Variables.html#General-Variables

I know, it's bad form to follow up to my own email, but here's a more
concrete reference stating that emacs will set HOME  when emacs
starts: 
http://www.gnu.org/software/emacs/manual/html_node/emacs/Windows-HOME.html

[Wherever Emacs finds your .emacs file], Emacs sets the value of the
HOME environment variable to point to it, and it will use that
location for other files and directories it normally creates in the
user's home directory. 

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Re: windows and home path

[Jerry Hill]

On Tue, Jan 24, 2012 at 11:10 AM, Andrea Crotti
andrea.crott...@gmail.com wrote:
 Ah yes thanks for the explanation, on Python 2.7 on Linux I don't see
 the same doc, it might have been updated later..
 Anyway I just want to make sure that I get always the same path,
 not depending on the program.

 From a first look it seems that just using os.getenv('HOMEPATH') on
 windows might make the trick..

It would not do the trick on my windows XP workstation here.  Your
target environments may be different, of course.  From a general
command prompt (cmd.exe) on my work machine, here's what you would
have to work with:

HOMEDRIVE=H:
HOMEPATH=\
HOMESHARE=\\server\share\userdirectory
USERPROFILE=C:\Documents and Settings\username

There is no HOME set here.  So, what's the right home directory for me
on this PC?  Depending on your opinion of right you could end up
with three different answers:  H:\, \\server\share\userdirectory,
or C:\Documents and Settings\username all seem like valid candidates
to me.  Just going by HOMEPATH isn't going to be helpful if I were to
run your code though.

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Re: Parsing a serial stream too slowly

[Jerry Hill]

On Mon, Jan 23, 2012 at 4:48 PM, M.Pekala mcdpek...@gmail.com wrote:

 Hello, I am having some trouble with a serial stream on a project I am
 When one sensor is running my python script grabs the data just fine,
 removes the formatting, and throws it into a text control box. However
 when 3 or more sensors are running, I get output like the following:

 Sensor 1: 373
 Sensor 2: 112$$M-160$G373
 Sensor 3: 763$$A892$

 I am fairly certain this means that my code is running too slow to
 catch all the '$' markers. Below is the snippet of code I believe is
 the cause of this problem...


That doesn't sound right.  Being too slow seems unlikely to produce the
wrong data...


def OnSerialRead(self, event):
text = event.data
self.sensorabuffer = self.sensorabuffer + text
self.sensorbbuffer = self.sensorbbuffer + text
self.sensorcbuffer = self.sensorcbuffer + text

if sensoraenable:
sensorresult = re.search(r'\$A.*\$.*', self.sensorabuffer )


Here, you search in sensorabuffer (which, by the way, would be much more
readable to me as sensor_a_buffer, as recommended by the PEP 8 style guide).



if sensorbenable:
sensorresult = re.search(r'\$A.*\$.*', self.sensorbenable)


here, you're not searching in the buffer, but in the enable flag.



if sensorcenable:
sensorresult = re.search(r'\$A.*\$.*', self.sensorcenable)


And here too.

Does that fix the problem?

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Re: Please don't use setuptools, the rotten .egg install system.

[Jerry Hill]

On Wed, Jan 18, 2012 at 1:24 PM, John Nagle na...@animats.com wrote:

  Please don't use setuptools, the so-called easy
 installation system in your packages.  It just makes things
 more complicated, adds dependencies, and needs too many weird
 options if things aren't exactly where it wants them.  Since
 setuptools is non-standard, it has to be installed before
 installing other things.


Please don't use any projects that are built with setuptools or easy
installation systems.  Problem solved.

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Re: Type object returned by the re.compile function

[Jerry Hill]

On Tue, Dec 27, 2011 at 4:56 PM, candide candide@free.invalid wrote:
 import re
 reo = re.compile('')
 reo.__class__
 Traceback (most recent call last):
  File stdin, line 1, in module
 AttributeError: __class__


I'm not going to comment on what type is returned from the various
functions in the re module, mostly because all I have installed
locally is 2.6, and I'm not sure if anything has changed in 2.7 or
3.2.

Instead, I will recommend a different tool for your  toolbox.  Take a
look at the type() builtin function (
http://docs.python.org/library/functions.html#type ).  Particularly,
instead of inspecting reo.__class__ in your example above, you can
print out type(reo).

At a guess, those objects are missing the __class__ attribute,
possibly because they are old style classes.

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Re: Upgraded Ubuntu - 11.10, Python - 2.7.2. Now psyco doesn't work?

[Jerry Hill]

On Tue, Dec 20, 2011 at 5:43 PM, John Ladasky lada...@my-deja.com wrote:
 I was running Ubuntu Linux 10.10, on which Python 2.6.6 was the
 standard distribution.  I succeeded in doing an alternate install of
 Python 2.7.2, over Ubuntu 10.10.  But I use so many packages in my
 code.  Dealing with the package dependencies, and the intricacies of
 invoking the right version of Python at the command prompt, were
 making me dizzy.  After a few hours of struggle, I just decided to
 upgrade my OS to Ubuntu 11.10, on which Python 2.7.2 is the standard
 distribution.

 I then installed numpy, scipy, and matplotlib, and confirmed that they
 work.  I needed just one more package to try my code: psyco.
 According to the Synaptic Package Manager of Ubuntu 11.10, there is a
 supported version of psyco for this OS revision, python-psyco
 1.6-2ubuntu1.  I downloaded it.  It installed.  But an attempt to
 import psyco gives me an ImportError at the python prompt.

From the psyco homepage ( http://psyco.sourceforge.net/ ) Python 2.7
is unsupported so far. Anyone interested in porting Psyco to it is
welcome. I started the work in a branch but it needs finishing.
That's the most recent news item on the home page, and it's dated July
16, 2010, about a year and a half ago.

I don't think psyco supports python 2.7.

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Re: Python horks on WinXP path names

[Jerry Hill]

On Thu, Dec 8, 2011 at 3:16 PM, Eric einazaki...@yahoo.com wrote:

 I'm running Python 2.7 on WinXP (ActiveState community version) and
 when I try to do this:

 if __name__ == '__main__':
root = Tkinter.Tk()
root.withdraw()
fileNames = tkFileDialog.askopenfilenames()
root.destroy()
print fileNames
 # windows filename gets
 for fileName in fileNames:
print fileName
file = open(fileName, 'r')
for line in file.readlines():
print line.strip()


 I get this:

 C:\Documents and Settings\eric\Desktop\PythonShoppython picker.py
 {C:/Documents and Settings/eric/Desktop/PythonShop/cereal.py}
 {
 Traceback (most recent call last):
  File picker.py, line 31, in module
file = open(fileName, 'r')
 IOError: [Errno 2] No such file or directory: u'{'

 That is, fileName is in a form that open() doesn't recognize.  On a
 BSD box the code works fine.  What's going on with the file name and
 how do I fix it?


Try replacing your current print fileNames line with the follwing:

print type(fileNames), repr(fileNames)

The behavior you're seeing seems to indicate that fileNames is really a
single filename (a single unicode string), rather than a list of file names
(a list containing strings).

I don't know why that would be, but it would be helpful to confirm that
that is, indeed, the problem.

I guess you should also double check that the version of the code you're
running on windows does, in fact, call tkFileDialog.askopenfilenames()
rather than tkFileDialog.askopenfilename()  The two calls are just one
letter different, but the first one is supposed to return a list, and the
second one is supposed to just return a single string.
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Re: tracking variable value changes

[Jerry Hill]

On Thu, Dec 8, 2011 at 3:17 PM, Catherine Moroney 
catherine.m.moro...@jpl.nasa.gov wrote:

 Is there some way to rewrite the code above so the change of a from
 1.0 to 100.0 is reflected in the dictionary.  I would like to use
 simple datatypes such as floats, rather than numpy arrays or classes.


No, there is not.  You would need to use a mutable data type, and float is
not mutable (neither are ints or strings).

-- 
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Re: Py and SQL

[Jerry Hill]

On Wed, Nov 30, 2011 at 3:30 PM, Verde Denim tdl...@gmail.com wrote:

 dbCursor1.execute('select lpad(' ', 2*level) || c Privilege, Roles and
 Users from ( select null p, name c from system_privilege_map where name
 like upper(\'%enter_privliege%\') union select granted_role p, grantee c
 from dba_role_privs union select privilege p, grantee c from dba_sys_privs)
 start with p is null connect by p = prior c')


I think this is your problem.  Your string is delimited with single quotes
on the outside ('), but you also have a mix of single and double quotes
inside your string.  If you were to assign this to a variable and print it
out, you would probably see the problem right away.

You have two options.  First, you could flip the outer quotes to double
quotes, then switch all of the quotes inside the string to single quotes (I
think that will work fine in SQL).  Second, you could use a triple-quoted
string by switching the outer quotes to ''' or .  Doing that would let
you mix whatever kinds of quotes you like inside your string, like this
(untested):

sql = '''select lpad(' ', 2*level) || c Privilege, Roles and Users from (
select null p, name c from system_privilege_map where name like
upper(\'%enter_privliege%\') union select granted_role p, grantee c from
dba_role_privs union select privilege p, grantee c from dba_sys_privs)
start with p is null connect by p = prior c'''

dbCursor1.execute(sql)

Once you do that, I think you will find that the enter_priviliege bit in
your SQL isn't going to do what you want.  I assume you're expecting that
to automatically pop up some sort of dialog box asking the user to enter a
value for that variable?  That isn't going to happen in python.  That's a
function of the database IDE you use.  You'll need to use python to ask the
user for the privilege level, then substitute it into the sql yourself.

-- 
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Re: Can I submit an issue with Python 2.5.6?

[Jerry Hill]

2011/11/29 Toshiyuki Ogura m...@live.jp

  I found a problem with Python 2.5.6.

...

 Can I submit the issue at bugs.python.org?
 I think many people are still using Python 2.5 because of Google App
 Engine and fixing bugs with 2.5 is still helpful.


I don't think they'll be accepted.  Python 2.5 is not slated to receive any
more releases, ever.  Not even source-only security fixes.  According to
http://www.python.org/getit/releases/2.5.6/, This release is the final
release of Python 2.5; under the current release policy, no security issues
in Python 2.5 will be fixed anymore.  Given that they're not even
accepting security patches, I'm sure they won't accept non-security
bugfixes either.

If your goal is to get your patch accepted and deployed on google's app
engine infrastructure, you could try getting a hold of someone at google,
and asking if they accept patches directly, since there will be no further
maintenance from the core python developers.  I have no idea how difficult
it would be to do that, or if there's any interest in accepting patches
against python 2.5 at google.

-- 
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Re: String splitting by spaces question

[Jerry Hill]

On Wed, Nov 23, 2011 at 12:10 PM, Massi massi_...@msn.com wrote:

 Hi everyone,

 I have to parse a string and splitting it by spaces. The problem is
 that the string can include substrings comprises by quotations which
 must mantain the spaces. What I need is to pass from a string like:

 This is an 'example string'

 to the following vector:

 [This, is, an, example string]

 Which is the best way to achieve this?



This sounds a lot like the way a shell parses arguments on the command
line.  If that's your desire, python has a module in the standard library
that will help, called shlex (http://docs.python.org/library/shlex.html).
Particularly, shlex.split may do exactly what you want out of the box:

Python 2.6.4 (r264:75708, Oct 26 2009, 08:23:19) [MSC v.1500 32 bit
(Intel)] on win32

 import shlex
 s = This is an 'example string'
 shlex.split(s)
['This', 'is', 'an', 'example string']


-- 
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Re: How to mix-in __getattr__ after the fact?

[Jerry Hill]

On Fri, Oct 28, 2011 at 1:34 PM, dhyams dhy...@gmail.com wrote:
 If I call __getattr__ directly, as in bessie.__getattr__('foo'), it
 works as it should obviously; so the method is bound and ready to be
 called.  But Python does not seem to want to call __getattr__
 appropriately if I mix it in after the object is already created.  Is
 there a workaround, or am I doing something wrongly?

Python looks up special methods on the class, not the instance (see
http://docs.python.org/reference/datamodel.html#special-method-lookup-for-new-style-classes).

It seems like you ought to be able to delegate the special attribute
access from the class to the instance somehow, but I couldn't figure
out how to do it in a few minutes of fiddling at the interpreter.

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Re: Reading pen drive data

[Jerry Hill]

On Sat, Sep 3, 2011 at 12:21 PM, mukesh tiwari mukeshtiwari.ii...@gmail.com
 wrote:

 I am getting
 Traceback (most recent call last):
  File Mount.py, line 7, in module
observer = QUDevMonitorObserver(monitor)
 NameError: name 'QUDevMonitorObserver' is not defined

 Could any one please tell me how to avoid this error .


It looks to me like that should be pyudev.QUDevMonitorObserver, shouldn't
it?

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Re: How to convert a list of strings into a list of variables

[Jerry Hill]

On Thu, Aug 18, 2011 at 11:19 AM, noydb jenn.du...@gmail.com wrote:
 I am being passed the list of strings.  I have variables set up
 already pointing to files.  I need to loop through each variable in
 the list and do things to the files.  The list of strings will change
 each time, include up to 22 of the same strings each time.

If you have a mapping of strings to values, you should just go ahead
and store them in a dictionary.  Then the lookup becomes simple:

def foo(list_of_strings):
mapping = {
bar0: /var/log/bar0.log,
bar1: /usr/local/bar/bar1.txt,
bar2: /home/joe/logs/bar2.log,
}
for item in list_of_strings:
filename = mapping[item]
do_something(filename)


(Untested)

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Re: Determine what msvcrt.getch() is getting?

[Jerry Hill]

On Tue, Aug 16, 2011 at 5:43 PM, John Doe jdoe@usenetlove.invalid wrote:
 Whatever msvcrt.getch() is returning here in Windows, it's not within
 the 1-255 number range. How can I determine what it is returning?

 I would like to see whatever it is getting.

Just print it.  Like this:

import msvcrt
ch = msvcrt.getch()
print (ch)

for a bit more information, do this instead:
import msvcrt
ch = msvcrt.getch()
print(type(ch), repr(ch), ord(ch))

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Re: Wait for a keypress before continuing?

[Jerry Hill]

On Tue, Aug 16, 2011 at 5:59 PM, John Doe jdoe@usenetlove.invalid wrote:
 No. I am running this from within Windows, all sorts of Windows.

What does that mean?  You seem very resistant to answering anyone's
questions about your code.  Is your code run from the command line, or
does it have a GUI?  If it has a GUI, what windowing toolkit are you
using?  If you have code that's not working, please, show us a short,
run-able bit of sample code that demonstrates the problem you're
experiencing. Describe the behavior you see, the behavior you expected
instead, and the full text of any traceback you may be getting.

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Re: Only Bytecode, No .py Files

[Jerry Hill]

On Fri, Jul 29, 2011 at 8:51 AM, John Roth johnro...@gmail.com wrote:
 Sorry. I thought what you posted was from the OP. I guess I don't
 really expect someone to post a completely irrelevant trace in a
 thread started by someone who has a problem.

I'm not sure why you would think that that post was by the original
poster, or that it was irrelevant.  It seems to me that it
demonstrated exactly the behavior Eldon was complaining about as a
normal part of the operation of lots of normal unix programs.  Thomas
even said that in the very first line of his post (after the quoted
bit).

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Re: What is xrange?

[Jerry Hill]

On Fri, Jul 29, 2011 at 3:36 PM, Billy Mays no...@nohow.com wrote:
 Is xrange not a generator?  I know it doesn't return a tuple or list, so
 what exactly is it?  Y doesn't ever complete, but x does.

 x = (i for i in range(10))
 y = xrange(10)

xrange() does not return a generator.  It returns an iterable xrange
object.  If you want the iterator derived from the iterable xrange
object, you can get it like this:  iterator = y.__iter__()

See http://docs.python.org/library/functions.html#xrange for the
definition of the xrange object.

http://www.learningpython.com/2009/02/23/iterators-iterables-and-generators-oh-my/
seems to cover the differences between iterables, iterators, and
generators pretty well.

Some more reading:
http://docs.python.org/howto/functional.html
http://www.python.org/dev/peps/pep-0255/
http://www.python.org/dev/peps/pep-0289/

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Re: How do I access IDLE in Win7

[Jerry Hill]

On Wed, Jul 27, 2011 at 5:26 PM, W. eWatson wolftra...@invalid.com wrote:
 .py=Python.File
 .pyw=Python.NoConFile
 Python.File=C:\Python25\python.exe %1 %*
 Python.File=C:\Python25\python.exe %1 %*
 Python.NoConFile=C:\Python25\pythonw.exe %1 %*

That all looks good.

 I cannot copy from the cmd window. It ends with [errorno 13] Permission
 denied to c:||Users\\Wayne\\idlerc\\recent-files.lst'

That sounds like the root of the problem, then.  I'm assuming Wayne is
your username, but I don't know why you wouldn't have permission to
access something in your own user directory.  Can you try deleting
that file in the windows explorer?  You could try messing with the
permissions, but I doubt you care about a recent file list that sounds
several months old.  You might even try removing (or renaming) the
whole C:\Users\Wayne\idlerc folder.  Idle should re-build anything it
needs if it's not there when you start up.

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Re: How do I access IDLE in Win7

[Jerry Hill]

On Wed, Jul 27, 2011 at 12:28 PM, W. eWatson wolftra...@invalid.com wrote:
 If I run cmd.exe and work my way down to  .../idlelib, I find nothing but
 idle.bat. strange. Hidden?  I can get into line mode by using python.exe.
 That is, I can type in print abc, and get a result.

So, you don't have an idle.py or idle.pyw in C:\Python26\Lib\idlelib\
(or where ever you installed python)?  If not, it sounds to me like
your python installation is screwed up.  I would re-install.

Jerry
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Re: How do I access IDLE in Win7

[Jerry Hill]

On Wed, Jul 27, 2011 at 3:34 PM, W. eWatson wolftra...@invalid.com wrote:
 On 7/27/2011 9:48 AM, Jerry Hill wrote:
 So, you don't have an idle.py or idle.pyw in C:\Python26\Lib\idlelib\
 (or where ever you installed python)?  If not, it sounds to me like
 your python installation is screwed up.  I would re-install.

 Yes, I have both. Neither shows anything on the monitor when I double click
 them.

Oh, I guess I misunderstood.  Go ahead and open that cmd.exe window
back up.  Please run the following and report back the results.  In
the cmd.exe window run:

assoc .py
assoc .pyw
ftype Python.File
ftype Python.NoConFile

Those four commands should show us how the python file associations
are set up on your computer.

Then, let's try to run idle and capture whatever error message is
popping up.  I don't think you've mentioned what version of python you
have installed.  The following is for 2.6, since that's what I have
installed here, but it should work on any other version if you swap in
your installation directory for the 2.6 one below.  Still in your
cmd.exe window, run the following:

c:\Python26\python.exe C:\Python26\Lib\idlelib\idle.py

If you get an exception, please copy and paste the details for us.  If
that works and opens idle, please try running this:

C:\Python26\Lib\idlelib\idle.py

Based on the behavior you've described so far, that ought to fail, and
hopefully give some sort of message or exception for us to diagnose.

PS: If you're just trying to get things working, and don't care what
might be wrong, I would recommend just re-installing python.  That
ought to clean up all the file associations and set things up properly
for you.  That's likely the quickest way to just get things working.

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