83 Topics
 | This snippet defines a function to merge sorted iterables containing similar items into a single iterable. Items are supposed to be sorted in ascending order. Only one item per iterable is stored at a time. |
| | This snippet defines 3 functions to create in a few seconds an image of a graph containing arbitrary python objects. It uses the module pygraphviz (available at [url]http://pypi.python.org/pypi/pygraphviz/[/url]). See the example use case at the end of the module.  |
| | The with statement allows all sorts of syntactic sugar in python. This snippet defines two contexts: [icode]inevitably[/icode] and [icode]preferably[/icode] which register a function call to be executed at the end of a block of statement. Although they are not very useful (the function call could be written directly at the … |
| | I thought users of the python forum could be interested in a seminar conference by Guido van Rossum about the design and implementation of the python language, so here is the link [url]http://irbseminars.intel-research.net/GuidoVanRossum.wmv[/url] (it may be easier to download the file first instead of reading it directly from your browser) |
| | This snippet defines a function [icode]exc_browse()[/icode] which displays the current python exception in the web browser. This can be useful to non web programmers who want a nicely displayed exception traceback (web frameworks usually include this feature). The idea of this function is to store the html code generated by … |
| | How would you safely round a floating point number to the nearest integer ? Python has the built in function [icode]round[/icode], but it returns a floating point number [code=python] >>> round(4.9) 5.0 >>> help(round) Help on built-in function round in module __builtin__: round(...) round(number[, ndigits]) -> floating point number Round … |
| | I'm looking for C++ libraries to manipulate real and/or rational polynomials. Does someone know such a library ? |
| | This snippet defines a class LebsegueSet which instances represent sets of real numbers, namely finite unions of intervals. Set theoretical, topological and measure theoretical operations are implemented in pure python. Use freely and enjoy ! |
| | This snippet defines a class OptCmd which adds line and options parsing capabilities to the python standard lib's cmd.Cmd class. It allows you to quickly write an extensible command line interpreter. To use this module, you will need [url=http://www.daniweb.com/code/snippet234768.html]this other code snippet[/url], saved as a module named 'argv.py'. Enjoy the … |
| | Some time ago, I was writing a small command line interpreter, with the help of [url=http://docs.python.org/library/cmd.html#module-cmd]the standard module cmd[/url] which offers minimal support for such tasks, and I had the problem that this module doesn't have a function to parse a command line to produce a list argv which can … |
| | This snippet provides 2 functions to create in memory a gziped archive of a sequence of files and directories, and to extract files from this archive. These functions are similar in effect to the linux commands [icode]tar czf[/icode] and [icode]tar xzf[/icode] but instead of writing an archive file on disk, … |
| | This snippet defines a function [b]chmod[/b] which uses symbolic strings to represent the mode (eg [b]u+rwx[/b]) like the shell command 'chmod'. |
| | Joining together ordered sample points (xi, yi) when ths xi's are different yields a piecewise linear continuous (P1) function. This snippet defines a handy class to manipulate these functions. It allows computing the value and the slope of the function at each point, arithmetic operations, absolute value, truncation and linear … |
| | This snippet defines a context to execute a block of statements in a different working directory (with the help of the with statement). After the block is exited, the initial working directory is restored, even if an exception has occurred in the with block. |
| | Suppose that I have a program named myprog, and I type this in a shell [code] $ myprog -z hello -m "this is a message" [/code] The function main in myprog will receive a char** argv containing the following strings [code] "-z", "hello", "-m", "this is a message" [/code] So … |
| | Printing a convenient [url=http://en.wikipedia.org/wiki/ANSI_escape_sequence]ansi escape sequence[/url] clears the terminal (if you're running python from a terminal). Similar techniques could be used to print in colors. |
| | Does anyone know how I can test if an object's type is a builtin type or a user defined type ? |
| | This snippet shows a fast and efficient way to cut strings in substrings with a fixed length (note that the last substring may be smaller).  |
| | When several producer threads put items in a queue.Queue, and a consumer thread gets items from the queue, there is no way for the consumer thread to tell the producers that they should stop feeding the queue. This snippet defines a subclass of Queue with a close method. After the … |
| | This snippet defines a cachedProperty decorator. A cached property differs from a property in that it's value is only computed the first time that the property is accessed and then stored in the object's dict for later use. If the object's attribute is explicitely deleted, it will be computed again … |
| | This snippet defines a function [icode]patfilter(pattern, rule, sequence)[/icode] which implements filtering a sequence of strings according to various criteria. The output is either a subsequence of strings, or a sequence of match objects. |
| | Many threads in daniweb's python forum deal with menu based programs which run in a terminal. This snippet defines a handy class, MenuCrawler, to help writing such programs. Subclassing from this base classes and adding methods corresponding to a given set of menus allows one to build the menu-based application. … |
| | This snippet defines a class which can group a collection of strings according to a given set of prefixes. Each string goes in the group of the longest prefix it contains. |
| | This snippet allows your code to use the Mendeleiev's periodic table of elements. It defines a single function [icode]mendeleiev_table()[/icode] which returns the table as a python list of lists. |
| | If you're not used to work with the standard module logging, this snippet will allow you to incorporate a logger in your application without effort. It gives you a starting point before you try to use more sophisticated features of the logging module. |
| | This is a command line utility which lists the names of all functions defined in a python source file with a [icode]def <name>[/icode] statement |
| | Consider the following script [code=python] #!/usr/bin/env python # foo.py import sys print sys.argv [/code] When I run this in a terminal with arguments, here is the output [code] $ ./foo.py -h hello -m "this is a string" ['./foo.py', '-h', 'hello', '-m', 'this is a string'] [/code] My question is: is … |
| | What do you think would be the best way to write this structure [code=python] if testA: actionA() if testB: actionB() if textC: actionC() else: actionDefault() else: actionDefault() else: actionDefault() [/code] if I want to write only one call to actionDefault() ? |
| | In python, a "function object", that is to say an object which can be called as a function, is simply an instance of a class which has a [icode]__call__[/icode] method. An example is [code=python] class FuncObj(object): def __call__(self, *args): print("args were %s." % str(args)) func = FuncObj() func(1,2,3) # output … |
| | Python 3.0 comes with a builtin [icode]print[/icode] function which breaks old code. In order to write code wich is compatible both with the 2.x series and with the 3.x series, I'm using the following [icode]Print[/icode] function [code=python] import sys def Print(*values, **kwd): fout = kwd.get("file", sys.stdout) sep = kwd.get("sep", " … |
| | The following program is able to download the python programs contained in a thread of the python forum. Just start the program, it will prompt you for the thread number and create a directory with the code extracted from the thread. I used it to download all the wx examples. … |
| | I'm on linux, and I'm using a command called 'espeak' which reads sentences on stdin and writes phonemes on stdout. Whe I run it in a console, the output is the following [code] bash$ espeak -q -v mb-fr4 -s160 bonjour tout le monde # <-- I type this input, the … |
| | In the Perl language, you can fork a child process with the following syntax [code=perl] open CHILD, " | programA | programB | program C"; print CHILD "this is an example input"; [/code] (at least, you can do this under linux). This statement starts 3 processes in fact; programA, B …  |
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