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

r"
"
g

Test String

Code Generator

Language

Generated Code

use strict; my $str = '{"Items":[{"ItemID":10198,"ItemType":null,"Subject":null,"SubjectID":14,"Area":null,"AreaID":18,"Topic":null,"TopicID":18,"SubTopicID":0,"ItemBankName":null,"Direction":"","ItemTitle":"Q.53","IsApproved":false,"Item":"\\u003cp\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003eThe\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e efficiency of the screw\\u0026nbsp;\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003ein %\\u0026nbsp;\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003eupto\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e two decimal places is\\u0026nbsp;\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e[quizky-text]\\u003c/span\\u003e\\u003c/p\\u003e","ItemPassageID":352,"Passage":"\\u003cp\\u003e\\u003cstrong\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003eStatement\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e for Linked Answer Questions 52 and 53:\\u0026nbsp;\\u003c/span\\u003e\\u003c/strong\\u003e\\u003cbr /\\u003e \\u003cspan style=\\"font-size: 14.7px;\\"\\u003eA load of 30 KN is raised by means of a screw jack having square threaded screw of pitch 12 mm. The spindle diameter is 50 mm. If a force of 350 N is applied at the end of a lever to raise the load, co-efficient of friction\\u0026nbsp;\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003eis\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e 0.15.\\u003c/span\\u003e\\u003c/p\\u003e","PassageTitle":null,"IsLinkedQuestion":false,"Points":0,"Explanation":"\\u003cp\\u003e\\u003cspan style=\\"font-family: Symbol;\\"\\u003eh\\u003c/span\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e =\\u0026nbsp;\\u003c/span\\u003e\\u003cimg style=\\"vertical-align: bottom;\\" src=\\"QUIZKYIMAGEREPO/docximg_1128711867_image197.png\\" alt=\\"\\" width=\\"54\\" height=\\"32\\" data-docx-image=\\"image197.emf\\" /\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e =\\u0026nbsp;\\u003c/span\\u003e\\u003cimg style=\\"vertical-align: bottom;\\" src=\\"QUIZKYIMAGEREPO/docximg_1128711867_image198.png\\" alt=\\"\\" width=\\"40\\" height=\\"31\\" data-docx-image=\\"image198.emf\\" /\\u003e\\u003cspan style=\\"font-size: 14.7px;\\"\\u003e = 33%\\u003c/span\\u003e\\u003c/p\\u003e","ItemBankID":0,"LOD":null,"LODID":2,"ItemBank":0,"QuestionPaper":0,"IsProofRead":false,"CorrectIndex":0,"QuestionPaperSectionID":0,"ItemOptionModel":null}],"ItemOptions":[{"ItemOptionID":37637,"ItemID":0,"Option":"\\u003cp\\u003e\\u003cspan style=\\"font-family: Arial; font-size: 12px;\\"\\u003e\\u0026nbsp;\\u003c/span\\u003e\\u003cspan style=\\"font-family: Arial; font-size: 12px;\\"\\u003e33.36\\u003c/span\\u003e\\u003c/p\\u003e","RHSOption":null,"MarkedIndex":null,"OrderNumber":null,"OptionIndex":0,"IsCorrect":false,"IsHTML":false,"RHSIsHTML":false,"ColumnID":0},{"ItemOptionID":37638,"ItemID":0,"Option":"\\u003cp\\u003e\\u003cspan style=\\"font-family: Arial; font-size: 12px;\\"\\u003e\\u0026nbsp;\\u003c/span\\u003e\\u003cspan style=\\"font-family: Arial; font-size: 12px;\\"\\u003e33.36\\u003c/span\\u003e\\u003c/p\\u003e","RHSOption":null,"MarkedIndex":null,"OrderNumber":null,"OptionIndex":0,"IsCorrect":false,"IsHTML":false,"RHSIsHTML":false,"ColumnID":0}]}'; my $regex = qr/(?<=src=\\").*?(?=\\")/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