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

/
/
sgm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

re = /(^[a-zA-z0-9]{32})/m str = '2629f4a363e64a36bbd86c01dfac5168 ff29ac3148394d1bbbcf85a7d0fd27dd c627930216bc439db8563451be4d8172 4ed84dd2bb68430e9c4d43884088b364 84ab4c45d2194651bfa6729ad81cdcb9 6fb2f2de90ab45f4976a699099d30697 2d80f4090d0244b4b92ce505874a5f95 f231e374e45a4f2da1b1dc2c6bcb5991 91d13e50695140a7b4d66a28880986ef 3ef3a3990b5e4870840068b500359fca 43fc4ca5d3a544a49aa0fb6d6e28ceb5 48e54b84562a41f98224773a163c3123 be7f7602169844138ef2a9ab66ac38b6 d2f3b5f91512431b86d943c89fa9b8c4 18ecb09cf4b94e4d91ec1b3efa97ea1f f7ed1df9200543baac16b1e094278f52 f5b54666ccd84b3b905a5092aaf35a48 c6a224f88afe4ebc8943cab7aedd5d21 da180ef24522404598d69e8eb4f071c5 66ae5365d8294605a9cbb6124773d8c4 ba491533d84540e384b4e47280cbdded d38e9d637dca4d6194ff860187ae9059 9113322aa1404a66ba28732ae59e603b ' subst = '<img src="https://vg05.met.vgwort.de/na/$1" width="1" height="1" alt="">' result = str.gsub(re, subst) # Print the result of the substitution puts result

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 Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html