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

Substitution

Processing...

Code Generator

Generated Code

re = /(^reflectance_\d_)(\S*)$/m str = 'reflectance_7_myd21a1_emissivity_29 reflectance_7_myd21a1_emissivity_29_savitzkygolay reflectance_7_myd21a1_emissivity_31 reflectance_7_myd21a1_emissivity_31_savitzkygolay reflectance_3_myd21a1_emissivity_32 reflectance_2_myd21a1_emissivity_32_savitzkygolay reflectance_1_mcd43a3_albedo_bsa_band1 reflectance_3_mcd43a3_albedo_bsa_band2 reflectance_7_mcd43a3_albedo_bsa_nir reflectance_7_mcd43a3_albedo_bsa_shortwave reflectance_7_mcd43a3_albedo_bsa_vis reflectance_7_mcd43a3_albedo_wsa_band1 reflectance_7_mcd43a3_albedo_wsa_band2 reflectance_7_mcd43a3_albedo_wsa_nir reflectance_7_mcd43a3_albedo_wsa_shortwave reflectance_7_mcd43a3_albedo_wsa_vis' subst = '($1)vs_$2' 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