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

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "^([^\\s]+) ([^\\s]+) ([^\\s]+) \\[([\\w:/]+\\s[+\\-]\\d{4})\\] \"(\\S+) /.*() ([^\\\\\"]+)\" (\\d{3}) (\\S+)"; final String string = "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:43:57 -0400] \"GET /images/ksclogo-medium.gif HTTP/1.0 \" 200 5866\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:44:07 -0400] \"GET /images/NASA-logosmall.gif HTTP/1.0 \" 200 786\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:44:11 -0400] \"GET /images/MOSAIC-logosmall.gif HTTP/1.0 \" 200 363\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:44:13 -0400] \"GET /images/USA-logosmall.gif HTTP/1.0 \" 200 234\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:43:39 -0400] \"GET / HTTP/1.0 \" 200 7131\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:44:15 -0400] \"GET /images/WORLD-logosmall.gif HTTP/1.0 \" 200 669\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:44:31 -0400] \"GET /shuttle/countdown/ HTTP/1.0 \" 200 4673\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:44:41 -0400] \"GET /shuttle/missions/sts-69/count69.gif HTTP/1.0 \" 200 46053\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:45:34 -0400] \"GET /images/KSC-logosmall.gif HTTP/1.0 \" 200 1204\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:45:46 -0400] \"GET /cgi-bin/imagemap/countdown69?293,287 HTTP/1.0 \" 302 85\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:45:48 -0400] \"GET /htbin/cdt_main.pl HTTP/1.0 \" 200 3714\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:45:52 -0400] \"GET /shuttle/countdown/images/countclock.gif HTTP/1.0 \" 200 13994\n" + "ix-li1-14.ix.netcom.com - - [08/Aug/1995:14:46:22 -0400] \"GET / HTTP/1.0 \" 200 7131\n" + "ix-li1-14.ix.netcom.com - - [08/Aug/1995:14:46:29 -0400] \"GET /images/ksclogo-medium.gif HTTP/1.0 \" 200 5866\n" + "ix-li1-14.ix.netcom.com - - [08/Aug/1995:14:46:35 -0400] \"GET /images/NASA-logosmall.gif HTTP/1.0 \" 200 786\n" + "ix-li1-14.ix.netcom.com - - [08/Aug/1995:14:46:37 -0400] \"GET /images/MOSAIC-logosmall.gif HTTP/1.0 \" 200 363\n" + "ix-li1-14.ix.netcom.com - - [08/Aug/1995:14:46:38 -0400] \"GET /images/USA-logosmall.gif HTTP/1.0 \" 200 234\n" + "ix-li1-14.ix.netcom.com - - [08/Aug/1995:14:46:40 -0400] \"GET /images/WORLD-logosmall.gif HTTP/1.0 \" 200 669\n" + "ix-li1-14.ix.netcom.com - - [08/Aug/1995:14:47:41 -0400] \"GET /shuttle/missions/sts-70/mission-sts-70.html HTTP/1.0 \" 200 20304\n" + "ix-sac6-20.ix.netcom.com - - [08/Aug/1995:14:47:48 -0400] \"GET /shuttle/countdown/count.html HTTP/1.0 \" 200 73231"; final Pattern pattern = Pattern.compile(regex); 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