Latest recipes tagged "python" but not "utilities"

Python-C-Interface: Check whether a given dictionary contains only valid keys (C)

2017-05-06T20:53:54-07:00

C recipe 580799 by Jorj X. McKie (c_interface, python).

This function is given a Python dictioanry and a list of string / unicode values. It will check whether all dictionary keys occur in this list and will return 1 (true) or 0 (false).

Implementing class-based callbacks in Python (Python)

2017-04-20T23:34:50-07:00

Python recipe 580788 by Vasudev Ram (callbacks, classes, functions, methods, objects, programming, python).

This is a follow-on to this recently posted recipe:

Implementing function-based callbacks in Python: https://code.activestate.com/recipes/580787-implementing-function-based-callbacks-in-python/?in=user-4173351

This new recipe shows how to create and use callbacks in Python, using classes with methods, instead of plain functions, as was done in the recipe linked above. All other points such as reasons and benefits for using callbacks, are more or less the same as mentioned in the previous recipe, except that class instances can carry state around, so to that extent, the two approaches are different.

https://jugad2.blogspot.in/2017/04/python-callbacks-using-classes-and.html

Implementing function-based callbacks in Python (Python)

2017-04-19T18:03:11-07:00

Python recipe 580787 by Vasudev Ram (callback, function, functions, python, techniques).

This recipe shows a simple way of implementing callbacks in Python. There are a few ways this can be done. The way shown here uses a simple function-based approach.

In a nutshell, a callback can be informally described like this: function a calls function b, and wants to make b run a specific independent chunk of code at some point during b's execution. We want to be able to vary which chunk of code gets called in different calls to b, so it cannot be hard-coded inside b. So function a passes another function, c, to b, as one argument, and b uses that parameter c to call the functionality that a wants b to call. (Function b may pass some parameters to the function represented by c, when it calls it. These could be either internally generated, passed from a, or a combination of both). So, by changing the value of the function c that gets passed to b (on different calls to b), a can change what chunk of code b calls.

More details and full code, description and output here:

https://jugad2.blogspot.in/2017/04/implementing-and-using-callbacks-in.html

Simulating an unless (reverse if) statement in Python (Python)

2017-02-23T22:38:50-08:00

Python recipe 580758 by Vasudev Ram (features, if, perl, programming, python, trick).

This recipe shows how to simulate an unless statement (a sort of reverse if, like Perl has), in Python. It is just for fun and as an experiment, not meant for real use, because the effect of unless can easily be got by negating the sense of the condition in an if statement.

More details and output here:

https://jugad2.blogspot.in/2017/02/perl-like-unless-reverse-if-feature-in.html

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

Classifying letters as vowels or consonants and counting their frequencies (Python)

2017-01-17T20:05:10-08:00

Python recipe 580749 by Vasudev Ram (assertions, comprehension, dict, dictionaries, dict_comp, python, python2, tuple, unpack).

This recipe shows how to take a string as input and classify the characters in it as vowels, consonants or neither. The frequency of each vowel is calculated and the frequency of all the consonants in total is calculated. The program logic is fairly simple, and uses a dictionary comprehension and a dict; the more interesting thing about it, is that it illustrates 8 Python language features in under 35 lines of code.

More details and sample output here:

https://jugad2.blogspot.in/2017/01/classifying-letters-and-counting-their.html

Give Python code a web plus command-line interface with hug (Python)

2017-01-05T16:57:15-08:00

Python recipe 580742 by Vasudev Ram (cli, commandline, hug, library, python, python3, user_interface, web, web_server).

This recipe shows how to take a Python function and wrap it with both a web and a command-line interface, somewhat easily, using the hug Python library. The example used shows how to wrap a function that uses the psutil library to get information on disk partitions. So you can see the disk partition info either via the web browser or the command line. The code for the recipe is shown below. It is also possible to wrap multiple functions in the same Python file, and expose all of them via both the web and the command-line.

More information and multiple sample outputs are available here:

https://jugad2.blogspot.in/2017/01/give-your-python-function-webcli-hug.html

Send autohotkey commands with Python (Python)

2017-01-02T01:33:31-08:00

Python recipe 580740 by Miguel Martínez López (autohotkey, python).

I use an asterisk (*) as a command line argument to read the autohotkey script from standard input (stdin). https://autohotkey.com/docs/Scripts.htm

Get disk partition information with psutil (cross-platform) (Python)

2016-12-23T18:05:41-08:00

Python recipe 580737 by Vasudev Ram (device, disk, file_system, psutil, python, sysadmin, system).

This is a recipe that shows how to easily get disk partition information, in a cross-platform manner (for the supported OSes), from your computer's operating system, using the psutil library for Python.

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.

TicTacToe (text based) (Python)

2016-11-27T07:10:56-08:00

Python recipe 580723 by Brandon Martin (artificial_intelligence, game, python, random, tac, tic, tictactoe, toe).

A text based version of TicTacToe for Python. Difficulty is not yet implemented, however, a computer player has been implemented that cannot be beaten. Posting just for fun.

Generate a PDF cheat sheet for converting 0 to 255 between bin / oct / dec / hex (Python)

2016-10-10T20:40:48-07:00

Python recipe 580706 by Vasudev Ram (binary, conversion, decimal, hexadecimal, octal, pdfwriter, pdf_generation, python, utility, xtopdf).

This recipe shows how to generate a PDF cheat sheet, that contains a table for conversion of the numbers 0 to 255 (the numbers that can fit in one byte) between binary, octal, decimal and hexadecimal representations. The table has four columns, one for each of those bases, and 256 rows, for the numbers 0 to 255.

TO use the table, you can look for a number, say in decimal, in the Dec(imal) column (or use the search function of your PDF viewer), then when you find it in some row, just look at the other 3 columns in that row, to find the value of that number in binary, octal and hexadecimal. And use the same procedure if starting with a number in any of the other three bases.

Put Peewee ORM data to PDF with xtopdf (Python)

2016-09-29T18:04:57-07:00

Python recipe 580704 by Vasudev Ram (conversion, converter, database, formats, orm, pdf, pdf_generation, peewee, python, python2, sqlite, xtopdf).

This recipe shows how some basics of how to fetch data from database tables managed by the Peewee ORM (a lightweight expressive ORM for Python) and write that data, formatted, to a PDF file. The recipe uses Python, the Peewee ORM and the xtopdf toolkit for PDF creation.

Create PDF control break reports with itertools.groupby and xtopdf (Python)

2016-07-23T22:17:29-07:00

Python recipe 580692 by Vasudev Ram (control, database, grouping, iterators, pdf, pdfwriter, pdf_generation, python, reportgeneration, reporting, sql, xtopdf).

This recipe shows how to create the classic control break style of report (a staple of data processing) using Python along with the groupby function from the itertools module, and xtopdf, a Python toolkit for PDF creation.

Convert Spelled out Integers (e.g. three thousand two hundred fifty) into Integers (e.g. 3250) and Vice Versa (Python)

2016-07-14T21:08:01-07:00

Python recipe 580689 by Chathura Gunasekara (integers, numbers, python, strings).

-Provides an isNumber function that can test if a floating point number is a number -str_to_int can convert a spelled out integer (e.g. 'one hundred thirty five') to its numeric form (e.g. 135) -int_to_str can convert an integer into its spelled out form.

Drive which Python functions are executed via a text file (Python)

2016-06-12T15:27:59-07:00

Python recipe 580681 by Vasudev Ram (adapter, configuration, dynamic, dynamic_method, python, runtime).

This recipe shows a simple way of externally controlling which Python functions (out out of some) in your program get executed. The control is done at run time, so no code changes to the program are needed, for different choices. The control is done using a text file.

Convert Spelled out Integers (e.g. three thousand two hundred fifty) into Integers (e.g. 3250) and Vice Versa (Python)

2016-06-09T20:35:26-07:00

Python recipe 580679 by Brandon Martin (integers, numbers, python, strings).

The many uses of randomness - Part 1 (Python)

2016-06-01T19:36:28-07:00

Python recipe 580674 by Vasudev Ram (python, python2, random, random_number).

This recipe shows some of the many uses of random numbers, using the random function from the random module from Python's standard library. A subsequent recipe or two will show other uses, both of other functions from the module, and for other purposes.

The uses shown in this recipe have to do with using random float values, and scaling them and offsetting them, and also how to get a repeated/predictable series of random numbers.

Register exit function (Python)

2016-05-31T00:42:47-07:00

Python recipe 580672 by Giampaolo Rodolà (exit, python, signal). Revision 3.

This is a function / decorator which registers a function which will be executed on "normal" interpreter exit or in case one of the signals is received by this process (differently from atexit.register()). Also, it makes sure to execute any other function which was previously registered via signal.signal(). If any, it will be executed after our own fun. The full blogpost explaining why you should use this instead of atexit module is here: http://grodola.blogspot.com/2016/02/how-to-always-execute-exit-functions-in-py.html

Shutdown your computer via E-mail - Python (Python)

2016-05-27T05:28:21-07:00

Python recipe 580668 by Burak Tandogan (computer, email, mail, python, script, shutdown). Revision 2.

Shutdown your computer via E-mail.

Basically, send an e-mail to your e-mail address SHUTDOWN YOURSELF {YEAR-MONTH-DATE} format in Subject. Your mail's SUBJECT must be in SHUTDOWN YOURSELF {YEAR-MONTH-DATE} format.