Top-rated recipes tagged "meta:loc=30"

Groupby (Python)

2004-02-12T07:05:02-08:00

Python recipe 259173 by Raymond Hettinger (algorithms). Revision 5.

Guido inspired SQL-like GROUPBY class that also encapsulates the logic in a Unix-like "sort | uniq".

Decorator to check method param types (Python)

2014-01-14T11:23:40-08:00

Python recipe 578809 by Andrey Nikishaev (decorators, method, typecheck).

This solution give possibility to check method param type, raise needed exception type, and also have good readability in the decorator definition.

Logging to console .. without surprises (Python)

2009-06-25T13:12:55-07:00

Python recipe 576819 by Sridhar Ratnakumar (logging). Revision 3.

logging.StreamHandler is not the best way to log to console .. as it prints everything to sys.stderr by default. You can configure it to log to sys.stdout .. but that means even error/exception will be printed to sys.stdout.

Summary reports using itertools.groupby (Python)

2004-09-10T13:20:37-07:00

Python recipe 304162 by Paul Moore (algorithms). Revision 2.

Lists of data grouped by a key value are common - obvious examples are spreadsheets or other tabular arrangements of information. In many cases, the new itertools groupby function introduced in Python 2.4 can provide a means of easily generating summaries of such information.

Easily create a Python REPL in Python (Python)

2016-10-31T21:53:30-07:00

Python recipe 580712 by Vasudev Ram (code_module, dynamic, evaluation, read_eval_print_loop, repl).

This recipe shows how to easily create a Python REPL (Read-Eval-Print Loop) in Python itself. This can allow the user to interact with a running Python program, including typing in Python statements at the REPL prompt, defining functions, using and changing variables that were set before the interaction started, and those variables modified during the interaction, will persist in the memory of the program, for any use, even after the interaction is over, as long as the program continues to run.

Blocks for python (Python)

2011-10-24T22:26:07-07:00

Python recipe 577920 by yoav glazner (block, lambda, python, style).

A simple block function that lets one send multi line blocks of code to a function it doesn't really act like a normal def/lambda but offers cool style

Tetration Fractal (Python)

2011-10-24T02:55:08-07:00

Python recipe 577917 by FB36 (fractal, math, mathematics).

Tetration Fractal.

Error logging with context manager and decorator (Python)

2007-09-19T06:52:58-07:00

Python recipe 531821 by Kent Johnson (shortcuts).

A context manager and decorator that wrap common exception trapping and handling code so they may be applied with just a single line of code in the client.

Run a task every few seconds (Python)

2001-06-18T04:31:57-07:00

Python recipe 65222 by Itamar Shtull-Trauring (threads).

The TaskThread class allows you to create threads that execute a specific action at a specified interval, by subclassing - just override the task() method. You can also shutdown a TaskThread without having to wait for it to finish "sleeping" (due to the use of threading.Event objects as an alternative to time.sleep()).

Show OS error codes and messages from the os.errno module (Python)

2017-03-01T17:18:23-08:00

Python recipe 580759 by Vasudev Ram (commandline, introspection, libraries, python, unix, utilities, windows).

This recipe is a simple Python introspection utility that displays the defined OS error codes and messages (that Python knows about) from the os.errno module. It works for both Python 2 and Python 3. For each kind of OS error defined in Python, it will display a serial number, the error code, and the corresponding error name, and English error message. E.g. the first few lines of its output are shown below:

$ py -2 os_errno_info.py

Showing error codes and names

from the os.errno module:

Python sys.version: 2.7.12

Number of error codes: 86

Idx Code Name Message

0 1 EPERM Operation not permitted

1 2 ENOENT No such file or directory

2 3 ESRCH No such process

3 4 EINTR Interrupted function call

4 5 EIO Input/output error

More information, full output and other details are available here:

https://jugad2.blogspot.in/2017/03/show-error-numbers-and-codes-from.html

Simulate C's switch statement (Python)

2016-12-11T16:28:50-08:00

Python recipe 580730 by Vasudev Ram (c, features, language, python, switch).

This recipe shows a Python construct that can behave somewhat like C's switch statement. It is not a perfect one-to-one simulation. But it does have some of the features of the C switch. One feature not supported is the fall-through feature in C's switch.

Convert Microsot Excel (XLSX) to PDF with Python and xtopdf (Python)

2015-11-22T22:15:25-08:00

Python recipe 579128 by Vasudev Ram (excel, formats, openpyxl, pdf, python, xlsx, xtopdf).

This recipe shows how the basics of to convert the text data in a Microsoft Excel file (XLSX format) to PDF (Portable Document Format). It uses openpyxl to read the XLSX file and xtopdf to generate the PDF file.

Design by contract on python vanilla (Python)

2013-11-05T20:50:30-08:00

Python recipe 578767 by Alan Cristhian Ruiz (demo, design_pattern, productivity). Revision 2.

The code below is an example that shows that we can do design by contract in python without any non-standard module.

Basic threaded Python TCP server (Python)

2012-09-19T17:59:01-07:00

Python recipe 578247 by Luis Martin Gil (python, server, tcp, thread). Revision 3.

TCP provides reliable, ordered delivery of a stream of bytes from a program on one computer to another program on another computer. Sometimes you need a quick deployment of a TCP server and here I bring to you a Python 2.* snippet of a threaded Python server.

Function that supports dividing timedelta by float (Python)

2012-05-17T13:47:07-07:00

Python recipe 578136 by Ben Hoyt (datetime, division, float).

Python 2.x doesn't support dividing a timedelta by a float (only works with int). This function adds support for that.

Iterator Offsetter (Python)

2012-04-16T13:08:55-07:00

Python recipe 577852 by Josh Bode (iterable, itertools, offset). Revision 2.

Produces a list of copies of an iterable that are offset by the supplied offsets.

8 queens (Python)

2010-09-30T15:35:12-07:00

Python recipe 577414 by mihai miulescu .

classical backtracking algorithm

Keyword Argument Injection with Python Decorators (Python)

2010-09-05T17:06:04-07:00

Python recipe 577382 by Ahmet Emre Aladağ (class, class_decorator, decorator, injection, variable). Revision 2.

In most of the object oriented codes we write, we need to set class attributes to the given argument values and this is a very line-consuming thing. To get over these redundant lines, I found a solution using decorators.

custom django login_required decorator (Python)

2006-10-24T08:54:07-07:00

Python recipe 498217 by Jian Ding Chen (web). Revision 2.

I found django's auth module is too complex for my needs, instead I wrote a relative simple one, but I miss the login_required decorator in django auth module, so I decide to write a new one.

Pass Javascript arrays to PHP (PHP)

2005-05-16T11:45:33-07:00

PHP recipe 414334 by Noah Spurrier (session).

This is a Javascript function that will convert a Javascript array to a string in PHP serialized format. You can pass this string to a PHP script and easily unserialize it to a PHP array.