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 = 'table4.id , table5.name , table6.name , table7.name , table8.name , table9.name , ddd ((\\s?\\w+(\\.\\w+)?\\s?\\,\\s?)*) select count(*) , max(table4.id) from table4,table5 left join tab2 on tab1.size = tab2.size , right join tab2 on tab1.size = tab2.size where id <> 1 having dd group by dd order by dd desc dd - 2 > 3; select user(); select * from user where id = (select * from dd where id = 1); select count(vdvdvdvfd) from table4,table5 where table4.id=table5.id; select tt.dd from table4,table5 where table4.id=table5.id; count(vdvdvdvfd) , max(fdvd) , sum(fdvd) , min(fdvd) , avg(fdvd) , version() , table , count(ff) , table ((\\*|((((count|max|sum|min|avg|version|database|user|round|ceil|floor|truncate|mod)\\((\\*|\\w+|\\s*)\\)\\s?,?\\s?)|(\\w+(.\\w+\\s+,\\s+))){1,}));?) ((((count|max|sum|min|avg|version|database|user)\\((\\*|\\w+|\\s*)\\)\\s?,?\\s?){1,});?) ((\\*|(((count|max|sum|min|avg|version|database|user|round|ceil|floor|truncate|mod)\\((\\*|\\w+|\\s*)\\)\\s?,?\\s?){1,}));?) select\\s+(\\*|((\\w+(\\.\\w+)?)+(\\s?,\\s?\\w+(\\.\\w+)?)*)|((\\w+\\([^\\s]|(\\w+\\.\\w+)?\\))(\\s+\\,\\s+)?)+)\\s+from\\s+(\\w+(\\s?,\\s?\\w+)*\\;?)(\\s+((\\w+\\s+join)\\s+(\\w+(\\.\\w)?\\s+on\\s+(\\w+(\\.\\w+)?\\s+=\\s+\\w+(\\.\\w+)?)?)(\\s+,\\s+)?)+)?(\\s+((limit\\s+(\\w+)?\\s?(\\,\\w+\\;)?)|((where)?\\s+?([^\\;]+\\s?;))))? select\\s+(\\*|((\\w+(\\.\\w+)?)+(\\s?,\\s?\\w+(\\.\\w+)?)*)|((\\w+\\([^\\s]|(\\w+\\.\\w+)?\\))(\\s+\\,\\s+)?)+)\\s+from\\s+(\\w+(\\s?,\\s?\\w+)*\\;?)(\\s+((\\w+\\s+join)\\s+(\\w+(\\.\\w)?\\s+on\\s+(\\w+(\\.\\w+)?\\s+=\\s+\\w+(\\.\\w+)?)?)(\\s+,\\s+)?)+)?(\\s+((limit\\s+(\\w+)?\\s?(\\,\\w+\\;)?)|((where)?\\s+?([^\\;]+\\s?;))))? select\\s+((\\*|(((count|max|sum|min|avg|version|database|user|round|ceil|floor|truncate|mod)\\((\\*|\\w+|\\s*)\\)\\s?,?\\s?){1,}));?)\\s+from\\s+(\\w+(\\s?,\\s?\\w+)*\\;?)(\\s+((\\w+\\s+join)\\s+(\\w+(\\.\\w)?\\s+on\\s+(\\w+(\\.\\w+)?\\s+=\\s+\\w+(\\.\\w+)?)?)(\\s+,\\s+)?)+)?(\\s+((limit\\s+(\\w+)?\\s?(\\,\\w+\\;)?)|((where)?\\s+?([^\\;]+\\s?;))))? '; my $regex = qr/((\*|((((count|max|sum|min|avg|version|database|user|round|ceil|floor|truncate|mod)\((\*|\w+|\s*)\)\s?,?\s?)|(\w+(.\w+\s+,\s+))){1,}));?)/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