Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
Processing...

Test String

Code Generator

Language

Generated Code

import re regex = re.compile(r"([a-zA-Z]+)[\s\-\.]+(\d{1,2})[\s\-\,]+(\d{4})") test_str = ("04/20/2009; 04/20/09; 4/3/09 7/8/71\n" "Mar-20-2009; Mar 20, 2009; March 20, 2009; Mar. 20, 2009; Mar 20 2009\n" "20 Mar 2009; 20 March 2009; 20 Mar. 2009; 20 March, 2009\n" "Mar 20th, 2009; Mar 21st, 2009; Mar 22nd, 2009\n" "Feb 2009; Sep 2009; Oct 2010\n" "6/2008; 12/2009\n" "6/1998 Primary Care Doctor:\n" "2009; 2010\n" "(4/10/71)Score-1Audit C Score Current: 9/27/75. \n" "1; 10/13/1976 Audit C Score,\n" "4-13-82 Other Child Mental occasion 5/21/77.\n" "1; 10/13/1976 Audit C\n" "(1988-now)\n" "B12 969 2007\n" "Lab: B12 969 2007\n" "Ely 708-810-7787 \n" "February, 2010\n" "URUGUAY September 1984.\n" "7HH, April 1985 Hx of Outpatient\n" "Venlafaxine 37.5mg daily: May, 2011: self-discontinued\n" ") Paxil (Jan 1978) : sedation\n" "LFTs WNL (October 1996)Problems Opioid dependence\n" "\"I wasn't getting anywhere\" (April 1988)Prior\n" "Prozac 20 mg daily: February, 1995: self-discontinued\n" "sLexapro (1988-now): Good response (anxiety)\n" "pOct 2015 - Admitted to Gray\n" "lNovember 1990 - NPCCHx of Outpatient Treatment: Yes") matches = regex.finditer(test_str) for match_num, match in enumerate(matches, start=1): print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}") for group_num, group in enumerate(match.groups(), start=1): print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html