Popular recipes tagged "meta:loc=56"

Find the arity of a Python function (Python)

2017-01-30T14:09:47-08:00

Python recipe 580753 by Vasudev Ram (functions, introspection, python, python2, reflection).

This recipe shows how to find the arity of a given Python function. The arity of a function is the number of arguments the function takes. The recipe uses the inspect module of Python.

More details and sample output (including some limitations) here:

https://jugad2.blogspot.in/2017/01/finding-arity-of-python-function.html

Simple command-line alarm clock in Python (Python)

2015-10-25T18:27:27-07:00

Python recipe 579117 by Vasudev Ram (alarm, clock, commandline, linux, python, time, unix, windows).

This recipe shows how to create a simple alarm clock in Python, that can be run from the command line in a terminal. It lets you specify the alarm time in minutes as a command line argument, and prints a wake-up message and beeps a few times, after that time arrives. You can use 0 for the minutes to test it immediately, including to adjust the volume using your speaker controls.

PyQt4 pressed modifier keys names as method argument by a decorator (Python)

2013-09-29T14:13:04-07:00

Python recipe 578675 by TNT (keys, modifier, pyqt). Revision 2.

This is a definition of a decorator function that checks which modifier keys are being pressed and adds a keyword argument to a method. This argument is a tuple of names (strings) of the modifier keys that have been pressed when the method was called (or triggered).

Riemann Zeta Function Graph (Python)

2013-07-21T08:03:39-07:00

Python recipe 578616 by FB36 (fractal, math, mathematics).

Riemann Zeta Function Graph

Validate XML with schemaLocation (Python)

2013-03-28T10:24:55-07:00

Python recipe 578503 by Mathias Loesch (schema, schemalocation, validation, xml). Revision 3.

Addresses problems described at:

http://stackoverflow.com/questions/2979824/in-document-schema-declarations-and-lxml https://mailman-mail5.webfaction.com/pipermail/lxml/2011-September/006153.html

Save and restore SHA-512 internal state (Python)

2013-03-03T18:05:42-08:00

Python recipe 578479 by Dima Tisnek (database, inner, pickle, restore, sha512, state).

If you have a very long input to hash, you may want to save your progress.

CPython doesn't normally let you, but it's easy to hack around via ctypes

The Iota language in Python (Python)

2013-04-02T01:19:28-07:00

Python recipe 578505 by Simon Forman .

Forgive me if you've heard this one before.

Generate Password and Bit Rank (Python)

2013-01-02T14:33:42-08:00

Python recipe 578397 by Captain DeadBones (passwords, password_generator, python).

The code generates passwords using different techniques and then checks them according to bit strength. Was written in context of Generating And Checking Passwords In Python.

Using ChainMap for embedded namespaces (Python)

2012-10-03T18:12:50-07:00

Python recipe 578279 by Steven D'Aprano (chainmap, metaclass, namespace).

The Zen of Python tells us:

Namespaces are one honking great idea -- let's do more of those!

Python already has an excellent namespace type, the module, but the problem with modules is that they have to live in a separate file, and sometimes you want the convenience of a single file while still encapsulating your code into namespaces. That's where classes are the usual solution, but classes need to be instantiated and methods need to be defined with a self parameter.

C++ has "namespaces" for encapsulating related objects and dividing the global scope into sub-scopes. Can we do the same in Python?

With a bit of metaclass trickery and the new ChainMap type from Python 3.3, we can!

Automatic Python PyObject ref-count management in C++ using a smart ptr (C++)

2011-12-19T15:24:03-08:00

C++ recipe 577985 by samh (extending).

Managing ref-counting is a complex and error prone business. If you choose C++ to extend or embed Python, you can simply use a modification on std::auto_ptr. Instead of calling delete on the managed pointer, it will decref it.

So now you can do:

auto_pyptr pyHelloStr(PyStr_FromString("Hello World!"));

and forget about having to decref it altogether! Just like auto_ptr you can get the PyObject * with get(), release it from managed control with release(), and rebind it with reset(new_ptr). You can also incref it by calling inc(), but be cautious as you can easily create a leak by increfing once to much.

Multi-threaded Mandelbrot Fractal (Python)

2011-05-01T17:33:20-07:00

Python recipe 577680 by FB36 (fractal, graphics, image, math, mathematics, thread, threading, threads). Revision 3.

Multi-threaded Mandelbrot Fractal.

Infix operators (Python)

2011-06-06T12:07:00-07:00

Python recipe 577738 by Animesh Kumar (oop).

Python has the wonderful "in" operator and it would be nice to have additional infix operator like this. This recipe shows how (almost) arbitrary infix operators can be defined.

Mandelbrot trajectories (Python)

2011-04-06T18:18:48-07:00

Python recipe 577642 by Kaushik Ghose (graph, interactive, matplotlib, plotting, widget).

An interactive graph to plot the trajectory of points on and off the mandelbrot set. Illustrates the use of sliders in matplotlib

Infix operators (Python)

2005-02-17T11:12:04-08:00

Python recipe 384122 by Ferdinand Jamitzky (oop). Revision 3.

Python has the wonderful "in" operator and it would be nice to have additional infix operator like this. This recipe shows how (almost) arbitrary infix operators can be defined.

Implementing Vertical Editing in Komodo 6 (JavaScript)

2010-09-29T19:09:35-07:00

JavaScript recipe 577406 by Eric Promislow (columns, komodo, verticalediting). Revision 4.

When editing a group of similar lines, it's very convenient to be able to press down-arrow and move to the same starting column position on the next line. (See an example at http://community.activestate.com/forum/vertical-editing ).

This code is for a Komodo 6 macro -- possibly the only tweak necessary to make it work on Komodo 5 is by commenting out the "macro.save()" code, but I haven't tested it. The discussion below will talk about how to use it.

Approximately Equal (Python)

2010-03-17T17:05:51-07:00

Python recipe 577124 by Steven D'Aprano (comparisons, distance, math, maths, numeric, string).

Generic "approximately equal" function for any object type, with customisable error tolerance.

When called with float arguments, approx_equal(x, y[, tol[, rel]) compares x and y numerically, and returns True if y is within either absolute error tol or relative error rel of x, otherwise return False. The function defaults to sensible default values for tol and rel.

For any other pair of objects, approx_equal() looks for a method __approx_equal__ and, if found, calls it with arbitrary optional arguments. This allows types to define their own concept of "close enough".

True-color Plasma Fractal (Python)

2016-01-22T22:44:33-08:00

Python recipe 577161 by FB36 (fractal, graphics, image, math). Revision 4.

True-color plasma fractal using non-recursive algorithm.

Binary Matrix Fractals using recursion (Python)

2010-03-27T15:15:49-07:00

Python recipe 577157 by FB36 (fractal, graphics, image, math).

Binary Matrix Fractals using recursion. It can convert any given binary matrix pattern into a fractal.

Convert Byte Size to String Representation (Python)

2012-04-13T19:55:07-07:00

Python recipe 576924 by Stephen Chappell (conversion, representation). Revision 4.

In anticipation of creating large data structure, it appeared to be helpful if the users could get an idea of how much memory (RAM in particular) would be used while attempting to create a large, multidimensional array. In order to convert the calculated size into a precise, human-readable format, the follow code was devised. In order to convert a number into an equivalent representation of bytes, just call the "convert" function while providing the number as its argument. The other functions are currently public in case anyone else finds them useful.

Quantitative Concentration Ratios Calculation (Python)

2009-05-08T01:41:29-07:00

Python recipe 576744 by donyo Ganchev .

Quantitative Concentration Ratios Calculation Script