Python - two different splits

In Python, there are two different split methods you can use to break up a string into a number of substrings, based on a particular separator. If you know exactly what character(s) your separator will be - e.g. exactly one space - the you can use the method in the string class. By if your separator is less well defined - e.g. if it's one or more space characters - then you'll want to use the split within the re class.

import re

space = re.compile(r'\s+')

data ="Perl Python   PHP Prolog Pascal"

langs = data.split(" ") 

print langs

langs = space.split(data)

print langs

How does that run?

['Perl', 'Python', '', '', 'PHP', 'Prolog\tPascal']

['Perl', 'Python', 'PHP', 'Prolog', 'Pascal']

The first split looks fairly poor - we've split at single space characters BUT the input string had multiple spaces in one place, and a tab in another

The second split - on a regular expression "one or more white space characters" worked much better, and is typically what you might use for data that was user entered or user edited.

There's a new example - [source here] - added, January 2011. Subject covered on our Python Courses.
(written 2007-03-15, updated 2011-01-29)

Associated topics are indexed under

Y108 - Python - String Handling
  [3469] Teaching dilemma - old tricks and techniques, or recent enhancements? - (2011-10-08)
  [3468] Python string formatting - the move from % to str.format - (2011-10-08)
  [3349] Formatting output in Python through str.format - (2011-07-07)
  [3218] Matching a license plate or product code - Regular Expressions - (2011-03-28)
  [3090] Matching to a string - what if it matches in many possible ways? - (2010-12-17)
  [2814] Python - splitting and joining strings - (2010-06-16)
  [2780] Formatted Printing in Python - (2010-05-25)
  [2765] Running operating system commands from your Python program - (2010-05-14)
  [2721] Regular Expressions in Python - (2010-04-14)
  [2692] Flexible search and replace in Python - (2010-03-25)
  [2406] Pound Sign in Python Program - (2009-09-15)
  [2284] Strings as collections in Python - (2009-07-12)
  [1876] Python Regular Expressions - (2008-11-08)
  [1608] Underlining in Perl and Python - the x and * operator in use - (2008-04-12)
  [1517] Python - formatting objects - (2008-01-24)
  [1195] Regular Express Primer - (2007-05-20)
  [970] String duplication - x in Perl, * in Python and Ruby - (2006-12-07)
  [954] Splitting Pythons in Bradford - (2006-11-29)
  [943] Matching within multiline strings, and ignoring case in regular expressions - (2006-11-25)
  [903] Pieces of Python - (2006-10-23)
  [773] Breaking bread - (2006-06-22)
  [560] The fencepost problem - (2006-01-10)
  [496] Python printf - (2005-11-15)
  [463] Splitting the difference - (2005-10-13)
  [324] The backtick operator in Python and Perl - (2005-05-25)

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