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
No Match

/
/
g

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = (r"(?i).*cc.*(cor.*ang.*|heart.*|icd.*|pace.*|coronary.*|cardi.*|aortic.*|lhc.*|.rhc.*|dual.*lead.*|cabg.*|trans.*echo.*)\n") test_str = ("CC AORTIC ROOT INJECTION\n" "CC CARDIOVERSION\n" "CC COR ANG BYPASS W/LHC\n" "CC COR ANG BYPASS W/R-LHC\n" "CC COR ANGIO BYPASS\n" "CC COR ANGIO W/LHC\n" "CC COR ANGIO W/R-LHC\n" "CC COR ANGIO W/RHC\n" "CC CORONARY ANGIO\n" "CC CORONARY ANGIO, CC COR ANGIO W/LHC\n" "CC DUAL LEAD ONLY, INSERT\n" "CC HEART CATH LEFT HEART\n" "CC HEART CATH LEFT HEART, CC HEART CATH R+L ADULT\n" "CC HEART CATH R+L ADULT\n" "CC ICD DUAL CHAMBER\n" "CC ICD GEN REMOVE\n" "CC ICD GEN REP MULT LEAD\n" "CC ICD GEN REPLACE\n" "CC ICD INS W/LEADS\n" "CC ICD LEAD TEST ONLY\n" "CC INTRACARDIAC EP 3D MAP\n" "CC IVUS CORONARY\n" "CC LHC FOR LV GRAM ONLY\n" "CC LHC FOR LV GRAM ONLY, CC COR ANGIO W/LHC\n" "CC PACE GEN REP DUAL LEAD\n" "CC PACEMAKER ATR + VENT\n" "CC PACEMAKER CHANGE DUAL\n" "CC PACEMAKER CHANGE SINGL\n" "CC PACEMAKER INSERT TEMP\n" "CC PERICARDIOCENTISIS\n" "CC PTLR CABG DES/PCI,SGL\n" "CC RHC FOR LV GRAM ONLY\n" "CC TRANS ESOPH ECHO/TEE\n\n") matches = re.finditer(regex, test_str) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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