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
Processing...

Test String

Substitution
Processing...

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "\\d\\d*[.]?\\d*\\d"; final String string = "\\par }{\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\insrsid13305240\\charrsid3175333 \\hich\\af1\\dbch\\af31505\\loch\\f1 Xray-source / Detector distance:}{\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\uld\\insrsid13305240\\charrsid3175333 \\tab \\tab }{\n" + "\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\insrsid13305240\\charrsid3175333 \\hich\\af1\\dbch\\af31505\\loch\\f1 529 mm}{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\insrsid13305240 \\hich\\af1\\dbch\\af31505\\loch\\f1 (20.861 inches)\n" + "\\par \\hich\\af1\\dbch\\af31505\\loch\\f1 Rotation axis / Detector \\hich\\af1\\dbch\\af31505\\loch\\f1 distance:}{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\uld\\insrsid13305240 \\hich\\af1\\dbch\\af31505\\loch\\f1 \\tab }{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \n" + "\\f1\\fs20\\insrsid13305240 \\hich\\af1\\dbch\\af31505\\loch\\f1 467.364 mm (18.4 inches)\n" + "\\par }{\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\insrsid13305240\\charrsid3175333 \\hich\\af1\\dbch\\af31505\\loch\\f1 Rotation axis / Xray-source distance:}{\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\uld\\insrsid13305240\\charrsid3175333 \n" + "\\hich\\af1\\dbch\\af31505\\loch\\f1 \\tab }{\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\insrsid13305240\\charrsid3175333 \\hich\\af1\\dbch\\af31505\\loch\\f1 62.5 mm}{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\insrsid13305240 \\hich\\af1\\dbch\\af31505\\loch\\f1\n" + "\\par \\tab \\hich\\af1\\dbch\\af31505\\loch\\f1 type:}{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\uld\\insrsid3017018 \\tab \\tab \\tab }{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\insrsid3017018 \\hich\\af1\\dbch\\af31505\\loch\\f1 step\n" + "\\par \\tab }{\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\insrsid3017018\\charrsid7233753 \\hich\\af1\\dbch\\af31505\\loch\\f1 # projections:}{\\rtlch\\fcs1 \\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\uld\\insrsid3017018\\charrsid7233753 \\tab \\tab }{\\rtlch\\fcs1 \n" + "\\ab\\af1\\afs20 \\ltrch\\fcs0 \\b\\f1\\fs20\\insrsid3017018\\charrsid7233753 \\hich\\af1\\dbch\\af31505\\loch\\f1 1440\n" + "\\par }{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\insrsid3017018 \\tab \\hich\\af1\\dbch\\af31505\\loch\\f1 # frames averaged:}{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\uld\\insrsid3017018 \\tab }{\\rtlch\\fcs1 \\af1\\afs20 \\ltrch\\fcs0 \\f1\\fs20\\insrsid3017018"; final String subst = "!!!!"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html