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 = '{ "name": "Medicare Annual Wellness Visit", "translate": false, "in_battery": false, "action": "submitTest.php", "conditionals_file": "conditionals-mwc.js", "alias": "MWC", "pdf_template": "annual_wellness_questionnaire.pdf", "info": "Please complete this checklist before seeing your doctor or nurse", "questions": [ { "title_eng": "What is your age?", "title_esp": "", "scoring_method": "", "range_type": "age", "is_last": false, "coords": { "y": 112, "x": 38 } }, { "title_eng": "Are you male or a female?", "title_esp": "", "scoring_method": "", "range_type": "gender", "is_last": false, "coords": { "y": 121, "x": 38 } }, { "title_eng": "During the past four weeks, has your physical and emotional health limited your social activities with family, friends and groups?", "title_esp": "", "scoring_method": "", "range_type": "state_slight", "is_last": false, "coords": { "y": 140, "x": 38 } }, { "title_eng": "During the past four weeks, how much body pain have you generally had?", "title_esp": "", "scoring_method": "", "range_type": "state_pain", "is_last": false, "coords": { "y": 154, "x": 38 } }, { "title_eng": "During the past four weeks, was someone available to help you if you wanted or needed help?<br/>(For example, if you felt very nervous, lonely or blue; got sick and had to stay in bed; needed someone to talk to; needed help with daily chores; or needed help just taking care of yourself.)", "title_esp": "", "scoring_method": "", "range_type": "affirm_qty", "is_last": false, "coords": { "y": 174, "x": 38 } }, { "title_eng": "During the past four weeks, what was the hardest physical activity you could do for at least 2 minutes?", "title_esp": "", "scoring_method": "", "range_type": "state_grade", "is_last": false, "coords": { "y": 194, "x": 38 } }, { "title_eng": "Can you handle your own money without help?", "title_esp": "", "scoring_method": "", "range_type": "boolean", "is_last": false, "coords": { "y": 206, "x": 38 } }, { "title_eng": "During the past four weeks, how would you rate your health in general?", "title_esp": "", "scoring_method": "", "range_type": "state_rate", "is_last": false, "coords": { "y": 222.5, "x": 39 } }, { "title_eng": "How have things been going for you in the past four weeks?", "title_esp": "", "scoring_method": "", "range_type": "life", "is_last": false, "coords": { "y": 238, "x": 39 } }, { "title_eng": "Are you having difficulties driving your car?", "title_esp": "", "scoring_method": "", "range_type": "boolean_drive", "is_last": false, "coords": { "y": 248, "x": 39 } }, { "title_eng": "Do you always fasten your seat belt when you are in the car?", "title_esp": "", "scoring_method": "", "range_type": "boolean_drive_b", "is_last": false, "coords": { "y": 52, "x": 136 } }, { "title_eng": "How often during the past four weeks have you been bothered by falling or dizziness when standing?", "title_esp": "", "scoring_method": "linear_gradation", "range_type": "state_freq", "is_last": false, "coords": { "y": 87, "x": 173 } }, { "title_eng": "How often during the past four weeks have you been bothered by sexual problems?", "title_esp": "", "scoring_method": "linear_gradation", "range_type": "state_freq", "is_last": false, "coords": { "y": 94, "x": 173 } }, { "title_eng": "How often during the past four weeks have you had trouble eating well?", "title_esp": "", "scoring_method": "linear_gradation", "range_type": "state_freq", "is_last": false, "coords": { "y": 100, "x": 173 } }, { "title_eng": "How often during the past four weeks have you been bothered by teeth or denture problems?", "title_esp": "", "scoring_method": "linear_gradation", "range_type": "state_freq", "is_last": false, "coords": { "y": 105, "x": 173 } }, { "title_eng": "How often during the past four weeks have you been bothered by problems using the telephone?", "title_esp": "", "scoring_method": "linear_gradation", "range_type": "state_freq", "is_last": false, "coords": { "y": 112, "x": 173 } }, { "title_eng": "How often during the past four weeks have you been bothered by tiredness or fatigue?", "title_esp": "", "scoring_method": "linear_gradation", "range_type": "state_freq", "is_last": false, "coords": { "y": 117, "x": 173 } }, { "title_eng": "Have you fallen 2 or more times during the past year?", "title_esp": "", "scoring_method": "", "range_type": "boolean", "is_last": false, "coords": { "y": 136, "x": 137 } }, { "title_eng": "Are you afraid of falling?", "title_esp": "", "scoring_method": "", "range_type": "boolean", "is_last": false, "coords": { "y": 147, "x": 137 } }, { "title_eng": "Are you a smoker?", "title_esp": "", "scoring_method": "", "range_type": "boolean_smoker", "is_last": false, "coords": { "y": 157, "x": 137 } }, { "title_eng": "During the past four weeks, how many drinks of wine, beer or other alcoholic beverages did you have?", "title_esp": "", "scoring_method": "", "range_type": "freq_drinks", "is_last": false, "coords": { "y": 176, "x": 137 } }, { "title_eng": "Do you excercise for about 20 minutes three or more times a week?", "title_esp": "", "scoring_method": "", "range_type": "freq_exer", "is_last": false, "coords": { "y": 190, "x": 137 } }, { "title_eng": "Have you been given any information to help you with hazards in your home that may hurt you?", "title_esp": "", "scoring_method": "", "range_type": "boolean", "is_last": false, "coords": { "y": 204, "x": 187 } }, { "title_eng": "Have you been given any information to help you with keeping track of your medications?", "title_esp": "", "scoring_method": "", "range_type": "boolean", "is_last": false, "coords": { "y": 209, "x": 187 } }, { "title_eng": "How often have you had trouble taking medications the way you are told to take them?", "title_esp": "", "scoring_method": "", "range_type": "freq_meds", "is_last": false, "coords": { "y": 224, "x": 137 } }, { "title_eng": "How confident are you that you can control and manage most of your health problems?", "title_esp": "", "scoring_method": "", "range_type": "state_confidence", "is_last": false, "coords": { "y": 238, "x": 137 } }, { "title_eng": "What is your race? (Check all that apply)", "title_esp": "", "scoring_method": "race", "range_type": "race", "is_last": true, "coords": { "y": 243, "x": 137 } } ] }'; my $regex = qr/coords.*\{[^}]+:.(\d+),[^}]+:.(\d*)\n.*}/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