Python - Revision history

Guillaume: /* Fusion Tables */

2011-12-29T11:29:36Z

‎Fusion Tables

Guillaume: /* Relevant modules for shell-alike scripting */

2011-12-29T11:29:03Z

‎Relevant modules for shell-alike scripting

Guillaume at 09:58, 29 December 2011

2011-12-29T09:58:57Z

Guillaume at 15:09, 27 December 2011

2011-12-27T15:09:53Z

Guillaume at 12:57, 20 December 2011

2011-12-20T12:57:20Z

Guillaume: /* Installing modules */

2010-02-25T01:02:07Z

‎Installing modules

Guillaume: 1 revision

2008-12-03T10:39:02Z

1 revision

192.168.20.177 at 16:30, 5 September 2008

2008-09-05T16:30:32Z

New page

[[Python]] is a rather popular interpreted language allowing object-oriented programming. Built under a modular open philosophy similar to [[Perl|Perl's]], it has a distinct opposite-minded philosophy to the ''There's more than one way to do it'' [[Perl]] moto, which is rather like ''There's one - and no more - obvious way to do it''. This produces uncluttered, clean and readable code.

==Installing modules==
Here's a sample command line for fetching and installing a python module under a bash shell:
> cd ''mymodules''
> wget http://''addressofmodule''/''module''.tar.gz
> tar -xvf ''module''.tar.gz
> cd ''module''
> python setup.py build
> sudo python setup.py install

Should you not be able to "sudo", then you need to install the module in your personal python module path (remember to define the <code>$PYTHONPATH</code> environment variable)
> python setup.py install --home ~/python/imports

===[[Mod-python]]===
[[Mod-Python]] is a module for the apache web server that allows to run python scripts and publish html.

===Numpy and scipy===
====Windows====
Check out this [http://www.scipy.org/Installing_SciPy/Windows link for windows].
====Linux====
=====FC5=====
For Fedora Core 5 (which makes NumPy 0.9.5 and NumPy 0.9.6 available via the fedora-extras yum repository):
yum install numpy
yum install lapack-devel blas-devel
Then download and unzip scipy-0.4.8 to, for example, /usr/local/src/. This version of SciPy is compatible with NumPy 0.9.5 and NumPy 0.9.6.
cd /usr/local/src/scipy-0.4.8
python setup.py install >& install.log

The install log will contain some errors about not finding atlas libraries, and recommending that you set the ATLAS environment variable. But doing this doesn't seem to make any difference, even if the atlas package is installed.

=====FC6=====
Numpy 1.0.1 and SciPy 0.5.2 are available in the fedora-extras yum repository. Installing the SciPy package should automatically cause the various dependencies (including NumPy) to be installed:
yum install scipy

====Test====
Once the binary are installed, test them with
>>> import numpy, scipy
>>> numpy.test()
>>> scipy.test()

===Not a root user?===
Should you not be granted root to the machine and still need to install a python module then add in your .bash_profile file the following code

> vim ~/.bash_profile
.bash_profile> PYTHONPATH=$PYTHONPATH:~/python/imports/lib/python
.bash_profile> export PYTHONPATH

==Best Practices==
Here we shortly define good practices and conventions that are advised to be followed when developping in Python. These will allow easy scalability of Python's code.

===Coding Conventions===
We'll try to keep them simple, short and concise.
When defining '''classes''':
* Name them with a '''capital letter''',
When defining '''data attributes''':
* Use a '''noun''',
When defining '''method attributes''':
* Use a '''verb'''.

===Documenting and commenting===
It's highly advisable to make use of Python's '''pydoc''' command that auto-generates man pages for Python's scripts and modules. Documentation must be inserted between '''"""''' tags.

> pydoc pymodule

===[http://en.wikipedia.org/wiki/Unit_test Unit testing]===
Following the latest hype at Google stating that ''Debugging sucks :( Testing rocks :)'', it's advisable to make use of python's built-in unit testing engine, '''doctest'''.
simply copy and paste python command-line's inputs with the expected outputs inside the documentation tags ('''"""''').

> python pymodule.py -v

===Exploring new modules===
It is recommended to use iPython to easily and quickly inspect new modules in Python. It comes natively with standard major *nix distros. Basically one can then use tabbing for autocompletion in a python command-line environment.
> ipython

===Python best-practice template===

====[http://refactormycode.com/codes/51-classtemplate The script]====
Here's a template python script ('''classtemplate.py''') that makes use of all of the above described coding conventions,
<code>[python,Y]
#! /usr/bin/python
""" A python primer. pydoc, doctest and classes.

Syntax:
To generate man pages:
> pydoc classtemplate

To try all the tests in doctest (and execute the script):
> python classtemplate.py -v
"""

#Class definition
class Table:
"""Class Table.

Doctest: here we insert python command lines inputs and outputs.
>>> print Table.database
http://access.com/db
"""

#Data attributes here
database='http://access.com/db'

#Method attributes here
def __init__(self,id,text):
"""Initializes the id and textlabel data attributes.

Doctest: Testing more data attributes defined at construction time
>>> x = Table(1,'coucou')
>>> print x.id
1
>>> print x.textlabel
coucou
"""
self.id=id
self.textlabel=text

#doctest -- "Debugging sucks :( Testing rocks :)"
def _test():
"""Inline Doctest activated. Cool! :D
This means that whenever the module is called in python

> python thismodule.py -v

the doctest function will try all the tests implemented in doctest.
"""
import doctest
doctest.testmod()

if __name__ == "__main__":
_test()
</code>

==== The man page ====
Here's the generated documentation

> pydoc classtemplate

Help on module classtemplate:

NAME
classtemplate - A python primer. pydoc, doctest and classes.

FILE
/users/left/guillaume/python/classtemplate.py

DESCRIPTION
Syntax:
To generate man pages:
> pydoc classtemplate

To try all the tests in doctest.
> python classtemplate.py -v

CLASSES
Table

class Table
| Class Table.
|
| Doctest: here we insert python command lines inputs and outputs.
| >>> print Table.database
| http://access.com/db
|
| Methods defined here:
|
| __init__(self, id, text)
| Initializes the id and textlabel data attributes.
|
| Doctest: Testing more data attributes defined at construction time
| >>> x = Table(1,'coucou')
| >>> print x.id
| 1
| >>> print x.textlabel
| coucou
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| database = 'http://access.com/db'

==== The unittests results ====
Here are the verbose output from the unit-tests (using doctest):
> python classtemplate.py -v

Trying:
print Table.database
Expecting:
http://access.com/db
ok
Trying:
x = Table(1,'coucou')
Expecting nothing
ok
Trying:
print x.id
Expecting:
1
ok
Trying:
print x.textlabel
Expecting:
coucou
ok
2 items had no tests:
__main__
__main__._test
2 items passed all tests:
1 tests in __main__.Table
3 tests in __main__.Table.__init__
4 tests in 4 items.
4 passed and 0 failed.
Test passed.

==Relevant modules for shell-alike scripting==
Here's a list of interesting module for interacting with the OS.
import os # getcwd, chdir
import shutil # file manip utilities: move, copyfile
import glob # file wildcards
import sys # command-line arguments processing, error, stderror redirection
import re # pattern matching, regexp
import math # mathematical functions
import urllib # http addressing. gets and posts method
import smtplib # send emails
import poplib # read emails
from datetime import date # date time manipulations
from timeit import Timer # performance timer
import unittest # unit testing --> agile, eXtreme development
import xmlrpclib # xml get, extract and parse.
from xml.dom import minidom

==Sample code==
'''NOTE: All samples should be corrected with tabulations when performing copy/paste actions!'''

===Celsius===
Transforms fahrenheits degrees into celsius degrees:

#!/usr/bin/python
import string, sys

# If no arguments were given, print a helpful message
if len(sys.argv)==1:
print 'Usage: celsius temp1 temp2 ...'
sys.exit(0)

# Loop over the arguments
for i in sys.argv[1:]:
try:
fahrenheit=float(string.atoi(i))
except string.atoi_error:
print repr(i), "not a numeric value"
else:
celsius=(fahrenheit-32)*5.0/9.0
print '%i\260F = %i\260C' % (int(fahrenheit), int(celsius+.5))

===Twitter===
Gets a list of users in the [[Twitter]] PublicTimeline. Requires the [[Twitter]] Api module.

#!/usr/bin/python
import twitter

api = twitter.Api()
statuses = api.GetPublicTimeline()
print [s.user.name for s in statuses]

===Xspf extract===
<code>[python,Y]
#! /usr/bin/python
""" Scrap mp3 files from xspf playlist
"""
import sys, string, urllib
from xml.dom import minidom

url=sys.argv[1]
feed=urllib.urlopen(url)
#feed=url
xspf=minidom.parse(feed)
locations=xspf.getElementsByTagName('location')
for location in locations:
track_url=string.strip(location.firstChild.data)
print track_url
</code>

==re - Regular Expressions==
===Web-scrapping===
Here are some web-scraping guidelines in Python:

#Here's a generic html code snippet:
In [298]: print string
<description hrel="come here" >Coucou Here <a href="" >I</a> am</description><description hrel="come here" >Coucou Here <a href="" >I</a> am</description>

#Let's isolate the content of ''description'' tags:
In [301]: subtr = re.sub(r'<description.*?>(.*?)</description>',r'\1&',string)
In [302]: print subtr
Coucou Here <a href="" >I</a> am&Coucou Here <a href="" >I</a> am&

#Let's purge the content from html formatting:
In [303]: re.sub(r"<.*?>","",subtr)
Out[303]: 'Coucou Here I am&Coucou Here I am&'

==External References==
*[http://docs.python.org/tut/ Python tutorial],
*[http://en.wikipedia.org/wiki/Python_(programming_language) Python@wikipedia],
*[http://www.scipy.org/ Scientific Python],
*[http://refactormycode.com/codes/51-classtemplate Refactormycode template].

[[Category:Linux]]
[[Category:Python]]
[[Category:Script]]
[[Category:Programming]]

@@ Line 264: / Line 264: @@
 === Fusion Tables ===
-How to install: Look for the google fusion table python package.
+How to install: Look for the google fusion table python package (not in the google code project).
   $ python setup.py install

@@ Line 14: / Line 14: @@
 ===Windows===
-  $ python setup.py build
+  $ python setup.py install
- $ copy build\lib\*.py %PYTHON%\Lib\site-packages
 ===Easy_install===

@@ Line 246: / Line 246: @@
   Test passed.
-==Relevant modules for shell-alike scripting==
+==Modules==
 Here's a list of interesting module for interacting with the OS.
   import os   # getcwd, chdir
@@ Line 262: / Line 262: @@
   import xmlrpclib # xml get, extract and parse.
   from xml.dom import minidom
 ==Sample code==

@@ Line 12: / Line 12: @@
 Should you not be able to "sudo", then you need to install the module in your personal python module path (remember to define the <code>$PYTHONPATH</code> environment variable)
   > python setup.py install --home ~/python/imports
 ===Easy_install===

@@ Line 65: / Line 65: @@
 When defining '''method attributes''':
 * Use a '''verb'''.
 ===Documenting and commenting===

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