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

/
/
gx

Test String

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 = "(,\\s*(*SKIP))?+\n" + "# Attempts to match a comma and advanced whitespaces,\n" + "# without backtracking;\n" + "# And if the comma is matched, use (*SKIP) verb,\n" + "# which advances the pointer if we fail to match the comma.\n\n" + "# Key - Value pairs not worthy of keeping.\n" + "(\n" + " \"(?!jobID\"|exec)[^\"]+\" # Check if we like this key.\n" + " \\s*+:\\s*+ # The colon, advance whitespaces.\n" + " ( # Check keys recursively.\n" + " \"[^\"]*\"\n" + " # String literals, boring.\n" + " | \\{(?2)?+(?>,\\s*(?2))*\\}\n" + " # Or: An object storing some key-value pairs\n" + " # we don't care about.\n" + " | \\[(?3)?+(?>,\\s*(?3))*\\]\n" + " # Or: An array storing some values\n" + " # we don't care about.\n" + " )\n" + ")\n" + "(?(1)|,?)\n" + "# Balance the comma (so the result string is still valid JSON)"; final String string = " \"2597401\":[{\"jobID\":\"2597401\",\n" + " \"account\":\"TG-CCR120014\",\n" + " \"user\":\"charngda\",\n" + " \"pkgT\":{\"pgi/7.2- 5\":{\"libA\":[\"libpgc.so\"],\n" + " \"flavor\":[\"default\"]}}, \n" + " \"startEpoch\":\"1338497979\",\n" + " \"runTime\":\"1022\",\n" + " \"execType\":\"user:binary\", \n" + " \"exec\":\"ft.D.64\",\n" + " \"numNodes\":\"4\",\n" + " \"sha1\":\"5a79879235aa31b6a46e73b43879428e2a175db5\",\n" + " \"execEpoch\":1336766742,\n" + " \"execModify\":\"Fri May 11 15:05:42 2012\",\n" + " \"startTime\":\"Thu May 31 15:59:39 2012\",\n" + " \"numCores\":\"64\",\n" + " \"sizeT\":{\"bss\":\"1881400168\",\"text\":\"239574\",\"data\":\"22504\"}}, \n" + " {\"jobID\":\"2597401\",\n" + " \"account\":\"TG-CCR120014\",\n" + " \"user\":\"charngda\",\n" + " \"pkgT\":{\"pgi/7.2-5\":{\"libA\":[\"libpgc.so\"],\n" + " \"flavor\":[\"default\"]}},\n" + " \"startEpoch\":\"1338497946\",\n" + " \"runTime\":\"33\" \"execType\":\"user:binary\",\n" + " \"exec\":\"cg.C.64\",\n" + " \"numNodes\":\"4\",\n" + " \"sha1\":\"caf415e011e28b7e4e5b050fb61cbf71a62a9789\",\n" + " \"execEpoch\":1336766735,\n" + " \"execModify\":\"Fri May 11 15:05:35 2012\",\n" + " \"startTime\":\"Thu May 31 15:59:06 2012\",\n" + " \"numCores\":\"64\",\n" + " \"sizeT\":{\"bss\":\"29630984\",\"text\":\"225749\",\"data\":\"20360\"}},\n" + " {\"jobID\":\"2597401\",\n" + " \"account\":\"TG-CCR120014\",\n" + " \"user\":\"charngda\",\n" + " \"pkgT\":{\"pgi/7.2-5\": {\"libA\":[\"libpgc.so\"],\n" + " \"flavor\":[\"default\"]}},\n" + " \"startEpoch\":\"1338500447\",\n" + " \"runTime\":\"145\",\n" + " \"execType\":\"user:binary\",\n" + " \"exec\":\"mg.D.64\",\n" + " \"numNodes\":\"4\",\n" + " \"sha1\":\"173de32e1514ad097b1c051ec49c4eb240f2001f\",\n" + " \"execEpoch\":1336766756,\n" + " \"execModify\":\"Fri May 11 15:05:56 2012\",\n" + " \"startTime\":\"Thu May 31 16:40:47 2012\",\n" + " \"numCores\":\"64\",\n" + " \"sizeT\":{\"bss\":\"456954120\",\"text\":\"426186\",\"data\":\"22184\"}},{\"jobID\":\"2597401\",\n" + " \"account\":\"TG-CCR120014\",\n" + " \"user\":\"charngda\",\n" + " \"pkgT\":{\"pgi/7.2-5\":{\"libA\":[\"libpgc.so\"],\n" + " \"flavor\":[\"default\"]}},\n" + " \"startEpoch\":\"1338499002\",\n" + " \"runTime\":\"1444\",\n" + " \"execType\":\"user:binary\",\n" + " \"exec\":\"lu.D.64\",\n" + " \"numNodes\":\"4\",\n" + " \"sha1\":\"c6dc16d25c2f23d2a3321d4feed16ab7e10c2cc1\",\n" + " \"execEpoch\":1336766748,\n" + " \"execModify\":\"Fri May 11 15:05:48 2012\",\n" + " \"startTime\":\"Thu May 31 16:16:42 2012\",\n" + " \"numCores\":\"64\",\n" + " \"sizeT\":{\"bss\":\"199850984\",\"text\":\"474218\",\"data\":\"27064\"}}],"; final Pattern pattern = Pattern.compile(regex, Pattern.COMMENTS); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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