Regular Expression in Python^•

Last modified on 01 Oct 2021.

We can select string with some patterns.

Import library

import re

Special characters

• . matches any character except a newline
• ^a all strings starting with 'a'
• a$ all strings ending with 'a'
• ab+ matches 'ab', 'abb' but not 'a', 'ac'.
• [bcr]at any characters within [] can be filled the space
• Using \ to escape special characters
  • \s : whitespace characters. \S: any except whitespace.
  • \b : empty strings (only at the beginning or end of a word). \B:
• cat|dog would match 'catfish' and 'hotdog' for begin and end characters
• [amk] will match 'a', 'm', or 'k`
• [0-9] will match any character that falls between 0 and 9
• [a-z] : lowercase
• [0-9]{4}: repeat the pattern [0-9] four times by writing
• a{m,n} matches from m to n repetitions of 'a'.
  • a{m,} matches from m to infinity repetitions of 'a'.

References

• Python docs – Regular Expression.

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