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

/
/
gm

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"^(?:(52\-)|(1\-))?(\()?(?(1)[0-9]{2,3}|[2-9][0-9]{2})(?(3)\)\s?|(\-|[.]|\s|))(?(1)[0-9]|[2-9])[0-9]{2}(?(4)\4|(?:\-|[.]|\s)?)[0-9]{4}(\s?(?:x|ext|ext.|extension|Ext|Ext.|Extension|#)\s?[0-9]+)?$" test_str = ("Regular valid formats\n\n" "225-586-7777\n" "(223)249-4444\n" "(223) 234-3344\n" "223.456.2222\n" "2253451111\n" "223 334 4444\n\n" "1-325-586-7777\n" "1-(923)249-4444\n" "1-(923) 234-3344\n" "1-923.456.2222\n" "1-9253451111\n" "1-923 234 4444\n\n" "52-125-586-7777\n" "52-(123)249-4444\n" "52-(123) 234-3344\n" "52-123.456.2222\n" "52-1253451111\n" "52-123 134 4444\n\n" "Valid formats with extensions\n\n" "1-800-661-3696 x14700\n" "1-800-661-3696x14700\n" "1-800-661-3696 Extension 14700\n" "1-800-661-3696 ext14700\n\n" "325-586-7777 x123\n" "(323)249-4444x123\n" "(323) 234-3344 Ext 123\n" "323.456.2222 ext 124\n" "3253451111ext. 123\n" "323 334 4444extension234\n" "(223)456 7891 x 123\n" "(223)456 7891 ext 123\n" "(223)456 7891 ext. 123\n" "(223)456 7891 Ext 123\n" "(223)456 7891 Ext. 123\n" "(910)456-8970 x12\n" "(910)456-8970 #12\n" "(910)456-8970 extension12456\n" "(910)456-8970 Extension 12456\n\n" "Invalid formats\n\n" "444000-1111\n" "444-0001111\n" "444.000-1111\n" "444000 1111\n" "444 0001111\n" "444 000.1111\n" "444.0001111\n" "444000.1111\n" "444-000.1111\n" "(4440001111\n" "444)0001111\n" "440001111\n" "444000111111\n\n" "125-586-7777\n" "(123)249-4444\n" "(123) 234-3344\n" "123.456.2222\n" "1253451111\n" "123 134 4444\n\n" "125-586-7777\n" "(123)249-4444\n" "(123) 234-3344\n" "123.456.2222\n" "1253451111\n" "123 134 4444\n\n" "Invalid formats with extensions\n\n" "12-125-586-7777\n" "12-(123)249-4444\n" "12-(123) 234-3344\n" "12-123.456.2222\n" "12-1253451111\n" "12-123 134 4444\n\n" "12-444000-1111\n" "12-444-0001111\n" "12-444.000-1111\n" "12-444000 1111\n" "12-444 0001111\n" "12-444 000.1111\n" "12-444.0001111\n" "12-444000.1111\n" "12-444-000.1111\n" "12-(4440001111\n" "12-444)0001111\n" "12-440001111\n" "12-444000111111\n\n" "1-888-720-1275 x2 x2\n" "1-888-720-1275 2\n" "1-888-720-1275 x\n" "1-888-720-1275 Ext\n" "888-720-1275x\n\n" "1-444000-1111\n" "1-444-0001111\n" "1-444.000-1111\n" "1-444000 1111\n" "1-444 0001111\n" "1-444 000.1111\n" "1-444.0001111\n" "1-444000.1111\n" "1-444-000.1111\n" "1-(4440001111\n" "1-444)0001111\n" "1-440001111\n" "1-444000111111") matches = re.finditer(regex, test_str, re.MULTILINE) 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