Python Programming

Last week we looked at the itertools module and how its iterator based functions can be faster than doing things from scratch. One of the examples showed a function using itertools.takewhile to be much faster than one using itertools.groupby. Some feedback we got, asked, what then is the point of groupby if it's just a slower version of other functionality?

The pycurl package is a Python interface to libcurl (http://curl.haxx.se/libcurl/). pycurl has been successfully built and tested with Python versions from 2.2 to the current 2.5.x releases.

Various Web surfing tasks that I regularly perform could be made much easier, and less tedious, if I could only use Python to fetch the HTML pages and to process them, yielding the information I really need. In this document I attempt to describe HTML processing in Python using readily available tools and libraries.

Louie provides Python programmers with a straightforward way to dispatch signals between objects in a wide variety of contexts. It is based on PyDispatcher, which in turn was based on a highly-rated recipe in the Python Cookbook. Louie is licensed under The BSD License.

This script mimics rsync which is available for the unix platform and have been ported to win32 one. It is a sort of advanced version of xcopy. Its aim is to selectively synchronize folders. More precisely it copy selective parts of a folder to a destination folder and in addition can remove parts of the destination folder that do not correspond to parts of the original folder. I like its capability to avoid copying files through the .cvsignore mechanism or the pattern matching mechanism and its capability to delete files that are no longer relevant, not to mention that because it's a python script anyone can easily fix or improve it as he whish.

Pycha is a very simple Python package for drawing charts using the great Cairo library. Its goals are: Lightweight Simple to use Nice looking with default values Customization It won't try to draw any possible chart on earth but draw the most common ones nicely. There are some other options you may want to look at like pyCairoChart Pycha is based on Plotr which is based on PlotKit. Both libraries are written in JavaScript and are great for client web programming. I needed the same for the server side so that's the reason I ported Plotr to Python. Now we can deliver charts to people with JavaScript disabled or embed them in PDF reports.

On Sat, 15 Dec 2001 17:53:49 -0800 (PST), David Brady <daves_spam_dodging_account at yahoo.com> wrote : >More win32all questions... is it possible to get the >handle of the window that currently has the focus? >win32gui.GetActiveWindow() fails because I'm looking >for a window outside the process of my Python script. E:\>python ActivePython 2.1.1, build 212 (ActiveState) Python 2.1.1 (#20, Jul 26 2001, 11:38:51) [MSC 32 bit (Intel)] on win32 Type "copyright", "credits" or "license" for more information. >>> import win32gui >>> import time >>> for x in range(10): ... time.sleep(1) ... print x, win32gui.GetWindowText(win32gui.GetForegroundWindow()) ... 0 cmd - python 1 cmd - python 2 (Untitled) * SciTE 3 (Untitled) * SciTE 4 ActivePython Documentation 5 ActivePython Documentation 6 PythonWin 7 PythonWin 8 PythonWin

Speech Recognition may be possible with COM. I found an example of how its done in Python.

Looks like foom is busy. Anyway, here is the verbatim translation of the script foom linked. I can't test it myself as no mike is installed on my machine. If you hear "Starting Succeeded", then, try to say one/two/three. NEED CoHelper.ahk.

SendKeys is a Python module for Windows (R) which can be used to send one or more keystrokes or keystroke combinations to the active window. SendKeys exports 1 function, SendKeys, and 1 exception, KeySe

What idioms should I use to make my code easier to read? Read "The Python Cookbook", especially the first few chapters. It's a great source of well-written Python code examples.

Use function factories to create utility functions. Often, especially if you're using map and filter a lot, you need utility functions that convert other functions or methods to taking a single parameter. In particular, you often want to bind some data to the function once, and then apply it repeatedly to different objects. In the above example, we needed a function that multiplied a particular field of an object by 3, but what we really want is a factory that's able to return for any field name and amount a multiplier function in that family:

Use zip and dict to map fields to names. zip turns a pair of sequences into a list of tuples containing the first, second, etc. values from each sequence. For example, zip('abc', [1,2,3]) == [('a',1),('b',2),('c',3)]. You can use this to save a lot of typing when you have fields in a known order that you want to map to names:

Here's what new-style classes have to offer: Properties: Attributes that are defined by get/set methods Static methods and class methods The new __getattribute__ hook, which, unlike __getattr__, is called for every attribute access, not just when the attribute can't be found in the instance Descriptors: A protocol to define the behavior of attribute access through objects Overriding the constructor __new__ Metaclasses (not discussed)

SVGMath is written in pure Python, with neither extension modules nor external dependencies. It runs on any platform where a modern Python environment (version 2.4 or higher) is available. It can be used either as a command-line script for batch-mode file conversion, or as a component to process MathML data in other Python applications.

A Pure-Python library built as a PDF toolkit. It is capable of: extracting document information (title, author, ...), splitting documents page by page, merging documents page by page, cropping pages, merging multiple pages into a single page, encrypting and decrypting PDF files. By being Pure-Python, it should run on any Python platform without any dependencies on external libraries. It can also work entirely on StringIO objects rather than file streams, allowing for PDF manipulation in memory. It is therefore a useful tool for websites that manage or manipulate PDFs.

PyChecker is a tool for finding bugs in python source code. It finds problems that are typically caught by a compiler for less dynamic languages, like C and C++. It is similar to lint. Because of the dynamic nature of python, some warnings may be incorrect; however, spurious warnings should be fairly infrequent.

Epydoc is a tool for generating API documentation for Python modules, based on their docstrings. For an example of epydoc's output, see the API documentation for epydoc itself (html, pdf). A lightweight markup language called epytext can be used to format docstrings, and to add information about specific fields, such as parameters and instance variables. Epydoc also understands docstrings written in reStructuredText, Javadoc, and plaintext. For a more extensive example of epydoc's output, see the API documentation for Python 2.5.