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 = '"{\\"cursor\\":\\"\\",\\"hits\\":3,\\"results\\":[{\\"id\\":65673,\\"num_records\\":14631,\\"assets\\":{\\"ip_addresses\\":14631,\\"password\\":14631,\\"target_url\\":14631,\\"keyboard_languages\\":14631,\\"user_sys_registered_owner\\":14484,\\"country\\":14631,\\"infected_machine_id\\":14631,\\"email\\":7346,\\"username\\":7285,\\"user_os\\":14631,\\"user_hostname\\":14631,\\"log_id\\":14631,\\"infected_time\\":14631,\\"country_code\\":14581}},{\\"id\\":65675,\\"num_records\\":2602,\\"assets\\":{\\"display_resolution\\":2602,\\"ip_addresses\\":2534,\\"user_browser\\":2602,\\"password\\":2602,\\"target_url\\":2602,\\"keyboard_languages\\":2602,\\"user_sys_registered_owner\\":2601,\\"country\\":2597,\\"infected_machine_id\\":2602,\\"email\\":943,\\"full_name\\":25,\\"av_softwares\\":2348,\\"username\\":1659,\\"infected_path\\":2534,\\"user_os\\":2602,\\"log_id\\":2602,\\"infected_time\\":2602,\\"country_code\\":2597,\\"timezone\\":2602}},{\\"id\\":65677,\\"num_records\\":139,\\"assets\\":{\\"display_resolution\\":139,\\"ip_addresses\\":139,\\"user_browser\\":139,\\"password\\":139,\\"target_url\\":139,\\"keyboard_languages\\":139,\\"user_sys_registered_owner\\":139,\\"country\\":139,\\"infected_machine_id\\":139,\\"email\\":3,\\"full_name\\":7,\\"av_softwares\\":139,\\"username\\":136,\\"infected_path\\":139,\\"user_os\\":139,\\"log_id\\":139,\\"infected_time\\":139,\\"country_code\\":139,\\"timezone\\":139}}]}" '; my $regex = qr/\"num_records\\":\s*(\d+)/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