Regular Expressions
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More power for string operations
Regular expressions allow to perform string search & replace operations using patterns.
import re
text = 'all ways lead to Rome'
Searching if something exists or not:
re.search('R...\s', text)
Finding all words:
re.findall('\s(.o)', text)
Replacing:
re.sub('R[meo]+','London', text)
How to find the right pattern for your problem
Finding the right RegEx requires lots of trial-and-error search. You can test regular expressionsonline before including them into your program:
http://www.regexplanet.com/simple/
Characters used in RegEx patterns:
Some of the most commonly used characters in Regular Expression patterns are:
\d - decimal character [0..9]
\w - alphanumeric [a..z] or [0..9]
\A - start of the text
\Z - end of the text
[ABC] - one of characters A,B,C
. - any character
^A - not A
a+ - one or more of pattern a
a* - zero or more of pattern a
a|b - either pattern a or b matches
(a) - re.findall returns a
\s - empty space
Ignoring case
If the case of the text should be ignored during the pattern matching, add , re.IGNORECASE to the parameters of any re function.
