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

use strict; my $str = '###################### # Must Match: ###################### Social Security Number Social Security Num Social Security No Social Security # Social Security# Social Security Social Sec Number Social Sec Num Social Sec No Social Sec # Social Sec# Social Sec Social Sec. Number Social Sec. Num Social Sec. No Social Sec. # Social Sec.# Social Sec. Soc. Sec Number Soc. Sec Num Soc. Sec No Soc. Sec # Soc. Sec# Soc. Sec Soc. Sec. Number Soc. Sec. Num Soc. Sec. No Soc. Sec. # Soc. Sec.# Soc. Sec. Social Insurance Number Social Insurance Num Social Insurance No Social Insurance # Social Insurance# SS Num S.S Num S.S. Num SSN# S.S.N# S.S.N.# SSN S.S.N S.S.N. SS # S.S # S.S. # SS# S.S# S.S.# SS ID SS I.D SS I.D. S.S. ID S.S.I.D. S.S. I.D S.S. I.D. SSID S.S.I.D S.S.I.D. SSN123- SSN 123 SSN# 123 SSN. 1234 SSN.123 # In context, lowercase: The following is a list of social insurance numbers: Yo, get d33z l33t ss# and profit! ###################### # Must Not Match: ###################### # More than social: Social Social Number Social Justice # No disallowed suffix: Social Security Administration S.S. Admin SS Admin Social Security Office S Sec Office Social Security Tax # Social required: Security ID Security Number # Invalid combination of security/insurance: Soc Sec Insurance No Social Insurance Sec No '; my $regex = qr/(?i)\bS(?:ocial|oc\.?|\.)? ?(?!(?:S(?:ecurity|ec\.?|\.)?|Insurance) ?(?:Admin|Insurance|Office|Sec|Tax))(?:(?:S(?:ecurity|ec\.?|\.)?)|(?:Insurance)) ?(?:N(?:\.|o\.?|umbers?|um\.?)?|I\.?D)?(?:\d|#|\.|\b)/mp; if ( $str =~ /$regex/g ) { print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n"; # print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n"; # print "Capture Group 2 is $2 ... and so on\n"; } # ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p' # Named capture groups can be called via $+{name}

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 Perl, please visit: http://perldoc.perl.org/perlre.html