Overview

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It's very common to need to extract data from program source.

The problem is that the Python likes to have its text indented means that literal data would often have extra spaces and lines that you really don't want. This drives many developers to drop in Python list data structures but that's tedious, more verbose, and often less legible.

textdata makes it easy to have clean, nicely-whitespaced data specified in your program, but to get the data that you want without extra whitespace cluttering things up. It's permissive of whitespace needed to make the program source look and work right, yet doesn't require that they they be seen in the resulting data.

Python string methods give easy ways to clean this text up, but it's no joy reinventing that particular text-cleanup wheel every time you need it--especially since many of the details are nitsy, dropping the code down into low-level constructs rather than just "give me the text!" And because the details can be a little tricky and frustrating, it's good to not just whip up some routine a la carte, but to use well-tested code.

This module helps clean up included text (or text lines) in a simple, reusable way that won't muck up your programs with extra code, and won't require constant wheel-reinvention.

Lines

data = lines("""
    There was an old woman who lived in a shoe.
    She had so many children, she didn't know what to do;
    She gave them some broth without any bread;
    Then whipped them all soundly and put them to bed.
""")

will result in:

['There was an old woman who lived in a shoe.',
 "She had so many children, she didn't know what to do;",
 'She gave them some broth without any bread;',
 'Then whipped them all soundly and put them to bed.']

Text

textlines is an optional entry point with the same parameters as lines, but that joins the resulting lines into a unified string.:

data = textlines("""
    There was an old woman who lived in a shoe.
    She had so many children, she didn't know what to do;
    She gave them some broth without any bread;
    Then whipped them all soundly and put them to bed.
""")

Yields:

"There was an old woman who lived in a shoe.\nShe ... to bed."
# where the ... abbreviates exactly the characters you'd expect

API Options

Both lines and textlines provide provide routinely-needed cleanups:

  • remove starting and ending blank lines (which are usually due to Python source formatting)
  • remove blank lines internal to your text block
  • remove common indentation
  • strip leading/trailing spaces other than the common prefix (leading spaces removed by request, trailing by default)
  • join lines together with your choice of separator string

lines(text, noblanks=True, dedent=True, lstrip=False, rstrip=True, join=False)

Returns text as a series of cleaned-up lines.

  • text is the text to be processed.
  • noblanks => all blank lines are eliminated, not just starting and ending ones. (default True).
  • dedent => strip a common prefix (usually whitespace) from each line (default True).
  • lstrip => strip all left (leading) space from each line (default False). Note that lstrip and dedent are mutually exclusive ways of handling leading space.
  • rstrip => strip all right (trailing) space from each line (default True)
  • join => either False (do nothing), True (concatenate lines), or a string that will be used to join the resulting lines (default False)

textlines(text, noblanks=True, dedent=True, lstrip=False, rstrip=True, join='\n')

Does the same helpful cleanups as lines(), but returns result as a single string, with lines separated by newlines (by default) and without a trailing newline.

Words

Often the data you need to encode is almost, but not quite, a series of words. A list of names, a list of color names--values that are mostly single words, but sometimes have an embedded spaces. textdata has you covered:

>>> words(' Billy Bobby "Mr. Smith" "Mrs. Jones"  ')
['Billy', 'Bobby', 'Mr. Smith', 'Mrs. Jones']

Embedded quotes (either single or double) can be used to construct "words" (or phrases) containing whitespace (including tabs and newlines).

words isn't a full parser, so there are some extreme cases like arbitrarily nested quotations that it can't handle. It isn't confused, however, by embedded apostrophes and other common gotchas. For example:

>>> words("don't be blue")
["don't", "be", "blue"]

>>> words(""" "'this'" works '"great"' """)
["'this'", 'works', '"great"']

words is a good choice for situations where you want a compact, friendly, whitespace-delimited data representation--but a few of your entries need more than just str.split().

Unicode and Encodings

textdata doesn't have any unique friction with Unicode characters and encodings. That said, any time you use Unicode characters in Python source files, care is warranted--especially in Python 2!

If your text includes Unicode characters, in Python 2 make sure to mark the string with a "u" prefix: u"". You can also do this in Python 3.3 and following. Sadly, there was a dropout of compatibility in early Python 3 releases, making it much harder to maintain a unified source base with them in the mix. (A compatibility function such as six.u from six can help alleviate much--though certainly not all--of the pain.)

It can also be helpful to declare your source encoding: put a specially-formatted comment as the first or second line of the source code:

# -- coding: <encoding name> --

This will usually be # -*- coding: utf-8 -*-, but other encodings are possible. Python 3 defaults to a UTF-8 encoding, but Python 2 assumes ASCII.

Notes

  • Version 1.1.3 switches from BSD to Apache License 2.0 and integrates tox testing with setup.py.

  • Version 1.1 added the words constructor.

  • Automated multi-version testing managed with the wonderful pytest, pytest-cov, and tox. Successfully packaged for, and tested against, all late-model versions of Python: 2.6, 2.7, 3.3, 3.4, as well as PyPy 2.5.1 (based on 2.7.9) and PyPy3 2.4.0 (based on 3.2.5). Module should work on Python 3.2, but dropped from testing matrix due to its age and lack of a Unicode literal making test specification much more difficult.)

  • Common line prefix is now computed without considering blank lines, so blank lines need not have any indentation on them just to "make things work."

  • The tricky case where all lines have a common prefix, but it's not entirely composed of whitespace, now properly handled. This is useful for lines that are already "quoted" such as with leading "|" or ">" symbols (common in Markdown and old-school email usage styles).

  • textlines() is now somewhat superfluous, now that lines() has a join kwarg. But you may prefer it for the implicit indication that it's turning lines into text.

  • It's tempting to define a constant such as Dedent that might be the default for the lstrip parameter, instead of having separate dedent and lstrip Booleans. The more I use singleton classes in Python as designated special values, the more useful they seem.

  • Automated multi-version testing managed with pytest and tox. Continuous integration testing with Travis-CI. Packaging linting with pyroma.

    Successfully packaged for, and tested against, all late-model versions of Python: 2.6, 2.7, 3.2, 3.3, 3.4, and 3.5 pre-release (3.5.0b3) as well as PyPy 2.6.0 (based on 2.7.9) and PyPy3 2.4.0 (based on 3.2.5).

  • The author, Jonathan Eunice or @jeunice on Twitter welcomes your comments and suggestions.

Installation

pip install -U textdata

To easy_install under a specific Python version (3.3 in this example):

python3.3 -m easy_install --upgrade textdata

(You may need to prefix these with "sudo " to authorize installation.)