Python Regular Expressions

Introduction

http://www.amk.ca/python/howto/regex/regex.html

http://www.tutorialspoint.com/python/python_reg_expressions.htm good tutorial

Reg Exp Syntax

http://docs.python.org/lib/re-syntax.html

• \d Matches any decimal digit; this is equivalent to the class [0-9].
• \D Matches any non-digit character; this is equivalent to the class [^0-9].
• \s Matches any whitespace character; this is equivalent to the class [ \t\n\r\f\v].
• \S Matches any non-whitespace character; this is equivalent to the class [^ \t\n\r\f\v].
• \w Matches any alphanumeric character; this is equivalent to the class [a-zA-Z0-9_].
• \W Matches any non-alphanumeric character; this is equivalent to the class [^a-zA-Z0-9_].

Compile for Performance

The sequence

prog = re.compile(pat)
result = prog.match(str)

is equivalent to

result = re.match(pat, str)

but the version using compile() is more efficient when the expression will be used several times in a single program.

Examples

The sequence

import re

s = 'abcdef'
re.match(r'^abcdef$', s)           # <_sre.SRE_Match object at 0x2b042001d238>
re.match(r'^abcdef$', s).group()   # 'abcdef'