Popular recipes not tagged "tkinter"

Uno (Text-Based) (Python)

2017-07-15T00:46:59-07:00

Python recipe 580811 by Brandon Martin (artificial_intelligence, cards, game, text_game, uno).

A text based recreation of the classic card game featuring functional AIs to play with. Some rules have been modified. User interface is text based, non-curses, using only simple python commands to draw it.

Insert a Text Box in a PDF page (fitz / PyMuPDF) (Python)

2017-06-29T22:54:25-07:00

Python recipe 580809 by Jorj X. McKie (fitz, mupdf, pdf, textbox).

This method inserts text into a predefined rectangular area of a (new or existing) PDF page. Words are distributed across the available space, put on new lines when required etc. Line breaks and tab characters are respected / resolved. Text can be aligned in the box (left, center, right) and fonts can be freely chosen. The method returns a float indicating how vertical space is left over after filling the area.

The Game of Tic Tac Toe in Python (Python)

2014-01-31T02:39:48-08:00

Python recipe 578816 by Captain DeadBones (beginner, game, python).

I thought this is a fun game to program. Easy to program and can teach a lot.

Captain DeadBones

Inserting Images on PDF Pages (Python)

2017-05-17T21:10:26-07:00

Python recipe 580803 by Jorj X. McKie (fitz, mupdf, pdf, pymupdf).

Version 1.11.0 of PyMuPDF allows putting an image on an existing PDF page. The following example puts the same image on every page of a given PDF - like a thumbnail.

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

Create Calendars on PDF with a few lines (Python)

2017-06-13T10:57:34-07:00

Python recipe 580805 by Jorj X. McKie (calendar, fitz, mupdf, pdf, pymupdf). Revision 2.

PyMuPDF (fitz) provides easy to use ways to create PDF documents out of simple texts.

An example is the text output of Python's calendar module. Here we take a starting year as script parameter and output a 3-page (A4 landscape) document with calendars for this and the following two years - in less than 20 lines of code.

How to handle PDF embedded files with PyMuPDF (Python)

2017-07-11T18:57:54-07:00

Python recipe 580796 by Jorj X. McKie (embedded_files, fitz, mupdf, pdf, pymupdf). Revision 3.

Version 1.11.0 (based on MuPDF v1.11) allows exporting, importing and interrogating files embedded in a PDF.

PDF "/EmbeddedFiles" are similar to ZIP archives (or the Microsoft OLE technique), allowing arbitrary data to be incorporated in a PDF and benefit from its unique features.

How to create a simple PDF Pie Chart using fitz / PyMuPDF (Python)

2017-07-10T16:07:51-07:00

Python recipe 580810 by Jorj X. McKie (fitz, pdf_generation).

PyMuPDF now supports drawing pie charts on a PDF page.

Important parameters for the function are center of the circle, one of the two arc's end points and the angle of the circular sector. The function will draw the pie piece (in a variety of options) and return the arc's calculated other end point for any subsequent processing.

This example creates a chart of the parliament seat distribution for political parties in the current German Bundestag.

Equally-spaced numbers (linspace) (Python)

2015-01-12T22:16:37-08:00

Python recipe 579000 by Andrew Barnert (float, linspace, range, spread).

An equivalent of numpy.linspace, but as a pure-Python lazy sequence.

Like NumPy's linspace, but unlike the spread and frange recipes listed here, the num argument specifies the number of values, not the number of intervals, and the range is closed, not half-open.

Although this is primarily designed for floats, it will work for Fraction, Decimal, NumPy arrays (although this would be silly) and even datetime values.

This recipe can also serve as an example for creating lazy sequences.

See the discussion below for caveats.

Shoelace Formula for polygonal area (Python)

2017-07-17T05:53:45-07:00

Python recipe 580812 by Paddy McCarthy (2d, area).

Copied, by author from "Paddy3118 Go deh!: Python investigation of the Shoelace Formula for polygonal area http://paddy3118.blogspot.com/2017/07/python-investigation-of-shoelace.html#ixzz4n43Dqhaa " Where there is more meat on the bone (under a different license though).

Inserting pages into a PDF with PyMuPDF (Python)

2017-05-17T21:15:26-07:00

Python recipe 580802 by Jorj X. McKie (fitz, mupdf, pdf, text_conversion). Revision 2.

Version 1.11.0 of PyMuPDF allows creating new PDF pages, as well as inserting images into existing pages.

Here is a script that converts any textfile into a PDF.

PDF Text Extraction using fitz / MuPDF (PyMuPDF) (Python)

2016-03-17T12:00:06-07:00

Python recipe 580626 by Jorj X. McKie (cbz, epub, mupdf, openxps, pdf, pymupdf, text_extraction, xps).

Extract all the text of a PDF (or other supported container types) at very high speed. In general, text pieces of a PDF page are not arranged in natural reading order, but in the order they were entered during PDF creation. This script re-arranges text blocks according to their pixel coordinates to achieve a more readable output, i.e. top-down, left-right.

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

groupby() For Unsorted Input (Python)

2017-05-12T10:40:58-07:00

Python recipe 580800 by Alfe (algorithm, datastructures, generators, grouping, lazy).

We all know the groupby() which is available in the itertools standard module. This one yields groups of consecutive elements in the input which are meant to be together in one group. For non-consecutive elements this will yield more than one group for the same key.

So effectively, groupby() only reformats a flat list into bunches of elements from that list without reordering anything. In practice this means that for input sorted by key this works perfect, but for unsorted input it might yield several groups for the same key (with groups for other keys in between). Typically needed, though, is a grouping with reordering if necessary.

I implemented a likewise lazy function (yielding generators) which also accepts ungrouped input.

How to Create a PDF with a Caustic Drawing (Python)

2017-06-18T17:43:47-07:00

Python recipe 580806 by Jorj X. McKie (fitz, mupdf, pdf, pymupdf).

Just a little demo on how to create simple drawings with PyMuPDF.

This script simulates what you see looking into your coffee mug, early in the morning after a long night of programming ...

Variable Abbreviations (Python)

2017-06-22T11:57:20-07:00

Python recipe 580807 by Alfe (abbreviations, contextmanager, variables, with).

One sometimes has nice long speaking names vor variables, maybe things like buildingList[foundIndex].height, but would like to address these in a shorter fashion to be used within a formula or similar where lots of longs names tend to confuse any reader trying to understand the formula. Physicists use one-letter names for a reason.

For this I wrote a small context provider which allows using short names instead of long ones:

with Abbr(h=buildingList[foundIndex].height, g=gravitationalConstant):
    fallTime = sqrt(2 * h / g)
    endSpeed = sqrt(2 * h * g)
print("Fall time:", fallTime)
print("End speed:", endSpeed)

For longer formulas this can reduce ugly multi-line expressions to clearly readable one-liners.

One could use this:

h = buildingList[foundIndex].height
g = gravitationalConstant
fallTime = sqrt(2 * h / g)
endSpeed = sqrt(2 * h * g)
del g, h
print("Fall time:", fallTime)
print("End speed:", endSpeed)

to achieve the same result, but

it would not look as clean and
the context provider solves the typical issues like cleanup on exception etc.

Just using local variables without cleanup (like above without the del statement) also is an option of course, but that would clutter the variable name space unnecessarily.

CAVEATS: The implementation of Abbr() is a hack. If used as intended and described here, it should work just fine, though. But the hackish nature forces me to mention some things: Since at compile time the compiler decides that the h and g in the example must be global variables (because they aren't assigned in the function), it produces byte code accessing global variables. The context provider changes the global variable structure to fill the needs. (Overridden already existing global variables of the same name get restored properly at context exit.) This means some things:

One cannot have a local variable of the same name in the frame surrounding the context manager.
Existing global variables are changed during the time of the context manager; so using names like sys or os for abbreviations might be a bad idea due to side-effects.

Guard against an exception in the wrong place (Python)

2017-06-25T17:17:43-07:00

Python recipe 580808 by Steven D'Aprano (context, exception, guard, manager). Revision 2.

Sometimes exception handling can obscure bugs unless you guard against a particular exception occurring in a certain place. One example is that accidentally raising StopIteration inside a generator will halt the generator instead of displaying a traceback. That was solved by PEP 479, which automatically has such StopIteration exceptions change to RuntimeError. See the discussion below for further examples.

Here is a class which can be used as either a decorator or context manager for guarding against the given exceptions. It takes an exception (or a tuple of exceptions) as argument, and if the wrapped code raises that exception, it is re-raised as another exception type (by default RuntimeError).

For example:

try:
    with exception_guard(ZeroDivisionError):
        1/0  # raises ZeroDivisionError
except RuntimeError:
    print ('ZeroDivisionError replaced by RuntimeError')


@exception_guard(KeyError)
def demo():
    return {}['key']  # raises KeyError

try:
    demo()
except RuntimeError:
    print ('KeyError replaced by RuntimeError')

How to Maintain PDF Links with fitz / PyMuPDF (Python)

2017-03-22T13:12:25-07:00

Python recipe 580765 by Jorj X. McKie (fitz, link, mupdf, pdf).

This REPL script example displays, updates, inserts and deletes links on a PDF page.