Popular recipes tagged "meta:loc=111"

Easy attribute setting and pretty representation (Python)

2014-12-03T09:55:06-08:00

Python recipe 578973 by Joakim Pettersson (attributes, lazy, traits). Revision 2.

Mix in one or more of these classes to avoid those tedious lines of administrative code for setting attributes and getting useful representations.

If you inherit HasInitableAttributes, your should be able to obj = eval(repr(obj)) without loosing data.

enthought.traits.api.HasTraits seems to mix in well also.

Tri-nary Tree: insertion and deletion (C++)

2014-02-07T04:21:50-08:00

C++ recipe 578825 by Chen (tree).

This contains the insertion and deletion implement for the tri-nary tree data structure.

Bloom Filter (Python)

2011-06-04T17:44:21-07:00

Python recipe 577684 by Raymond Hettinger (big_table, bloom_filter, sets, spelling_checker, spell_checker). Revision 18.

Space efficient, probabilistic set membership tester. Has no False Negatives but allows a rare False Positive.

Restricted dictionary (Python)

2012-02-16T21:39:02-08:00

Python recipe 578042 by arnoques (datastructures, dict, dictionary, record).

It's a dictionary that's restricted to a tuple of allowed keys. Any attempt to set an invalid key raises an error.

Yet Another Python Generator... (Python)

2011-12-19T08:14:55-08:00

Python recipe 577990 by Barry Walker (audio, demo, generator, linux, signal, sound, source, sweep).

Aha, but not what big guns were expecting...

LF Audio Sweep Generator.

Another kids level project to do for yourselves...

This is a Python DEMO to show the power of the sound card using Linux to generate an Audio Sweep Signal from 4KHz down to 100Hz and back again.

Written in such a way that anyone can understand how it works... This is for Linux and Python 2.x.x. Read the code for much more information, and...... A Python 3.x.x version is here:-

http://www.linuxformat.com/forums/viewtopic.php?t=14411

Enjoy finding simple solutions to often VERY difficult problems...

Bazza, G0LCU...

Calculate the MRO of a class (Python)

2011-06-11T08:31:09-07:00

Python recipe 577748 by Steven D'Aprano (c3, classes, method, mro, order, resolution).

This function allows you to calculate the Method Resolution Order (MRO, or sometimes linearization) of a class or base classes. This is the so-called "C3" algorithm, as used by Python (new-style classes, from version 2.3 and higher). The MRO is the order of base classes that Python uses to search for methods and attributes. For single inheritance, the MRO is obvious and straight-forward and not very exciting, but for multiple inheritance it's not always obvious what the MRO should be.

Bloom Filter (Python)

2011-08-08T00:14:35-07:00

Python recipe 577829 by sivarama sarma (big_table, bloom_filter, sets, spelling_checker, spell_checker).

Space efficient, probabilistic set membership tester. Has no False Negatives but allows a rare False Positive.

A script evaluating PSNR metric of two YUV420 frames (Python)

2011-04-08T07:26:45-07:00

Python recipe 577645 by Denis Gorodetskiy (comparison, difference, frame, metric, psnr, video, yuv). Revision 2.

A script evaluating PSNR metric of two YUV420 frames usage: psnr.py filename1.yuv filename2.yuv frame_width frame_height

Alternatively if filename1 contains width and height in the form file-1200x1600.yuv, the script will extract width and height of a frame from the filename. Then usage even simplier: psnr.py filename1-1200x1600.yuv filename2.yuv

Sphere (Python)

2010-05-06T12:28:12-07:00

Python recipe 577218 by Fouad Teniou (mathematics). Revision 3.

A sphere is a ball, similar to a circle in three dimension, and all its surface’s points are equidistant from the centre.

However, the distance from the centre point to the surface is called the radius, and the equation of the sphere is : (x-a)² + (y-b)² + (z-c)² = r² .

(a,b,c) are the coordinates of the centre and r is the radius.

Available disk space monitoring for concurrent writes (Python)

2010-03-25T01:10:14-07:00

Python recipe 577140 by Mateyuzo (files, multiprocessing, stat, writing). Revision 5.

A DiskSpaceProctor is registered with a SyncManager to be shared by forked processes and threads. This object will check the available free space and add up filesz of concurrent writes. If there is not enough space for the requesting write, an exception is raised.

EXIF-date-based JPEG files rename using PIL (Python)

2009-02-10T07:28:48-08:00

Python recipe 576646 by Denis Barmenkov (date, exif, jfif, jpeg, jpg, photo, pil, rename). Revision 4.

Rename JPEG files according to EXIF-date using PIL [library].

If global variable CREATE_HARDLINK is set, script creates Windows (XP) batch file for creating hardlink version of source files.

PIL available here: http://www.pythonware.com/products/pil/

SyncFiles (Python)

2008-12-13T21:28:57-08:00

Python recipe 576584 by Collin Stocks (backup, consistency, files, gnu, gpl, just_in_case, oop, pickle, state_machine, storage, sync, synchronize). Revision 3.

This module allows you to handle and protect from inconsistencies sets of files that must all be saved at the same time. It does this be creating backups and temporary files. It has been moderately tested for bugs.

Handling ANSI Terminal. (Python)

2010-02-09T05:51:23-08:00

Python recipe 574451 by Louis RIVIERE (ansi, linux, system, terminal). Revision 9.

This function can be used, with or instead of print, to get ANSI output.

Paint 2.0 (Python)

2007-03-28T15:30:34-07:00

Python recipe 511436 by Stephen Chappell (graphics).

This program was adapted from the SAMPLES directory that comes with Python. It allows two people to draw on a program with someone else watching and, at the same time watch what the other person is drawing also.

Separating Pattern Implementation from Your Code (Python)

2006-08-26T07:11:20-07:00

Python recipe 496993 by Jinghong Chen (oop).

Separate pattern implementation from your code so that you can reuse the implementation elsewhere.

The following code is an example that shows a reusable implementation of the Observer pattern of the GoF book.

Install MQ Connection Factory. (Tcl)

2005-10-18T22:50:16-07:00

Tcl recipe 442453 by Patrick Finnegan (websphere).

Install MQ Connection Factory at node level.

Integrating Twisted reactor with IPython (Python)

2005-04-22T01:26:20-07:00

Python recipe 410670 by Matthew Scott (debugging).

Runs the Twisted reactor event loop in a thread alongside an IPython shell, for introspecting a running Twisted process.

Find duplicate file names (Python)

2005-01-28T11:12:48-08:00

Python recipe 364953 by Artur de Sousa Rocha (files).

This script looks for files with identical file names. If requested, file sizes are also compared. You can search current directory or a list of directories specified on the command line. Search can be restricted to files with names containing a string, or with names matching a regular expression. Paths to duplicates are printed in groups separated by empty lines.

Table objects with operations in SQL-like syntax. (Python)

2004-09-02T13:21:24-07:00

Python recipe 286192 by Uwe Schmitt . Revision 5.

This recipe implements a simple Table class which allows searching in a syntax similar to SQLs WHERE statement. So if t is Table, t.a == 3 finds all rows, where the column named "a" has the value 3. Intersection and unions of search results are possible too, for examples look at the __main__ part below.

"Oneliner" for reverse/sort/extend strings/tuple/lists NOT in place (Python)

2002-04-07T03:51:55-07:00

Python recipe 119596 by H. Krekel (shortcuts). Revision 3.

If you like obfuscated but powerful Oneliners you will really enjoy this one. It allows to use reverse, sort and extent "on the fly" with tuples, strings or list types. It returns a new instance of the same type as the input type. Extending a tuple results in a new tuple. Sorting a string results in a new string and so on. Thanks to Patrick Maupin since version 1.2 it handles Null-Strings and tuples correctly.

Though the functionality can be expressed in a 290-character "Oneliner" i recommend that you use the longer 15-line code (at the end) as it is more understandable and "pythonic".