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

use strict; my $str = '(?(DEFINE)(?<internal_name_char_s>[^\\x85\\n\\r\\v\\t\\\\\\/\\:\\*\\"\\?\\<\\>\\|])(?<external_filesc_name_char_s>[^\\x85\\n\\r\\v\\t\\\\\\/\\:\\*\\"\\?\\<\\>\\|\\s])(?<external_folderesc_name_char_s>[^\\x85\\n\\r\\v\\t\\\\\\/\\:\\*\\"\\?\\<\\>\\|\\s\\.])(?<folder_name_s>\\g\'external_filesc_name_char_s\'\\g\'internal_name_char_s\'{1,258}\\g\'external_filesc_name_char_s\'|\\g\'external_folderesc_name_char_s\'\\g\'external_filesc_name_char_s\'|\\g\'external_filesc_name_char_s\'\\g\'external_folderesc_name_char_s\'|\\g\'external_folderesc_name_char_s\')(?<extension_char_s>[a-z0-9])(?<extension_s>\\g\'extension_char_s\'{1,260})(?<file_name_s>(?:\\g\'external_filesc_name_char_s\'\\g\'internal_name_char_s\'{1,258}\\g\'external_filesc_name_char_s\'|\\g\'external_filesc_name_char_s\'{1,2})(?=\\.\\g\'extension_s\'\\Z))(?<ipv4_number_s>(?:[12]\\d\\d)|(?:\\d\\d)|(?:\\d))(?<ipv4_s>(?:\\g\'ipv4_number_s\'\\.){3}\\g\'ipv4_number_s\'(?:\\:\\d+)?)(?<named_drive_root_s>[a-z]\\:\\/)(?<file_protocol_root_s>file\\:\\/\\/\\/\\g\'named_drive_root_s\')(?<smb_root_s>\\/\\/)(?<hyper_text_root_s>https?\\:\\/\\/))(?#definition is complete)\\A(?!\\Z)(?<all_until_last_name>(?<root>(?<fixed_root>\\/|\\g\'named_drive_root_s\'|\\g\'file_protocol_root_s\'|(?<remote_root>\\g\'smb_root_s\'|\\g\'hyper_text_root_s\')(?:(?<ipv4>\\g\'ipv4_s\')(?:\\/(?!\\Z)|))?)|(?<relative_root>\\.{1,2}\\/(?:\\.\\.\\/)*))?(?<body>(?:\\g\'folder_name_s\'\\/)*?))(?<last_folder_or_file_name>(?<file_full_name>(?<file_short_name>\\g\'file_name_s\')\\.(?:(?<shortcut_extension>lnk)|(?<remote_extension>url)|(?<general_extension>\\g\'extension_s\'))(?!\\/))|(?:(?<folder_name>\\g\'folder_name_s\')\\/?))?\\Z'; my $regex = qr/\(\?\(DEFINE\)(?<definition>(?<=(?:[^\\](?:\\\\)+)|[^\\])\(\?\<(?<name>[\w-[0-9]]\w*?)\>(?<content>(?#internals shallow)(?:(?:(?<=(?:[^\\](?:\\\\)+)|[^\\])\[(?:(?<=(?:[^\\](?:\\\\)+)|[^\\])(?:\\\[|\\\])|[^\[\]])*(?<=(?:[^\\](?:\\\\)+)|[^\\])\])|(?:(?<=(?:[^\\](?:\\\\)+)|[^\\])\(\?(?:\!|\=|\:|\<\!|\<\=)(?#internals deep)(?:(?<=(?:[^\\](?:\\\\)+)|[^\\])(?:\\\(|\\\)|\\\[|\\\])|[^\(\)\[\]])+(?<=(?:[^\\](?:\\\\)+)|[^\\])\))|(?:(?<=(?:[^\\](?:\\\\)+)|[^\\])(?:\\\(|\\\)|\\\[|\\\])|[^\(\)\[\]]))+)(?<=(?:[^\\](?:\\\\)+)|[^\\])\))*(?<=(?:[^\\](?:\\\\)+)|[^\\])\)/p; 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