Popular recipes tagged "python" but not "game" and "math"

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.

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

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

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

Unix tee-like functionality via a Python class (Python)

2017-03-31T14:30:30-07:00

Python recipe 580767 by Vasudev Ram (cli, command, commandline, linux, python, tee, unix, utilities, windows).

The Unix tee commmand, when used in a command pipeline, allows you to capture the output of the preceding command to a file or files, while still sending it on to standard output (stdout) for further processing via other commands in a pipeline, or to print it, etc.

This recipe shows how to implement simple tee-like functionality via a Python class. I do not aim to exactly replicate the functionality of the Unix tee, only something similar.

More details and sample output here:

https://jugad2.blogspot.in/2017/03/a-python-class-like-unix-tee-command.html

[xtopdf] Publish Delimiter-Separated Values (DSV data) to PDF (Python)

2016-12-17T19:08:33-08:00

Python recipe 580736 by Vasudev Ram (commandline, csv, data, files, formats, pdf, pdf_generation, python, tsv, utilities, xtopdf).

This recipe shows how to publish delimiter-separated values (a commonly used tabular data format) to PDF, using the xtopdf toolkit for PDF creation. It lets the user specify the delimiter via one of two command-line options - an ASCII code or an ASCII character. As Unix filters tend to do, it can operate either on standard input or on input filenames given as command-line arguments. In the case of multiple inputs via files, each input goes to a separate PDF output file.

A simple text file pager in Python (Python)

2017-02-10T21:34:45-08:00

Python recipe 580755 by Vasudev Ram (command, commandline, pagination, paging, python, text, utilities, windows).

This recipe shows how to create a simple text file pager in Python. It allows you to view text content a page at a time (with a user-definable number of lines per page). Like standard Unix utilities, it can either take a text file name as a command-line argument, or can read the text from its standard input, which can be redirected to come from a file, or to come from a pipe. The recipe is for Windows only, though, since it uses the msvcrt.getch() function, which is Windows-specific. However, the recipe can be modified to work on Unix by using things like tty, curses, termios, cbreak, etc.

More details here:

https://jugad2.blogspot.in/2017/02/tp-simple-text-pager-in-python.html

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.

Batch conversion of text files to PDF with fileinput and xtopdf (Python)

2016-11-07T20:28:01-08:00

Python recipe 580715 by Vasudev Ram (batch, batchmode, conversion, files, pdf, pdfwriter, python, text, text_processing, utilities, xtopdf).

This recipe shows how to do a batch conversion of the content of multiple text files into a single PDF file, with a) an automatic page break after the content of each text file (in the PDF output), b) page numbering, and c) a header and footer on each page.

It uses the fileinput module (part of the Python standard library), and xtopdf, a Python library for conversion of other formats to PDF.

xtopdf is available here: https://bitbucket.org/vasudevram/xtopdf

and a guide to installing and using xtopdf is here:

http://jugad2.blogspot.in/2012/07/guide-to-installing-and-using-xtopdf.html

Here is a sample run of the program:

python BTTP123.pdf text1.txt text2.txt text3.txt

This will read the content from the three text files specified and write it into the PDF file specified, neatly formatted.

Merge unique items from multiple lists into a new list (Python)

2016-04-05T18:11:49-07:00

Python recipe 580634 by Johannes S (lists, merge, python, set). Revision 2.

Suppose you have multiple lists. You want to print all unique items from the list. Now, what you could do is merge the lists into one_big_list (e.g., a + b +c), and then iterate over each item in one_big_list, etc. The solution proposed here gets this done faster and in one line of code. How? By using a python set. A python set is a dictionary that contains only keys (and no values). And dictionary keys are, by definition, unique. Hence, duplicate items are weeded out automatically. Once you have the set, you can easily convert it back into a list. As easy as that!

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).

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

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

A command-line musical alarm clock (Python)

2016-12-30T19:06:32-08:00

Python recipe 580739 by Vasudev Ram (alarm, audio, clock, multimedia, music, playsound, python, time, utilities, utility).

This is a simple musical alarm clock in Python. You pass a command-line argument specifying the time in minutes after which the alarm should go off. When that time arrives, it plays a musical sound.

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

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.

Simple directory list command with filename wildcard support (Python)

2016-12-02T20:52:56-08:00

Python recipe 580724 by Vasudev Ram (commandline, directory, file, filesystem, python, utilities).

This recipe shows a simple directory listing program. It can accept multiple command-line arguments specifying filenames. These filenames can include wildcard characters like * (asterisk) and ? (question mark), as is common in OS command shells like bash (Unix) and CMD (Windows). Tested on Windows but should work on Unix too, since it uses no OS-specific functions, or rather, it does use them, but that happens under the hood, within the libraries used.

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.