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 = "@font-face\\s* # Match @font-face and some spaces\n" + "( # Start group 1\n" + " \\{ # Match \\{\n" + " (?: # A non-capturing group\n" + " [^\\{\\}]+ # Match anything except \\{\\} one or more times\n" + " | # Or\n" + " (?1) # Recurse/rerun the expression of group 1\n" + " )* # Repeat 0 or more times\n" + " \\} # Match \\}\n" + ") # End group 1\n"; final String string = ".someclass0 {\n" + " background: url('http://images/someimage.png') no-repeat;\n" + "}\n\n" + "@font-face {\n" + " font-family: 'FontAwesome';\n" + " src: url(\"fonts/fontawesome-webfont.eot?v=4.0.3\");\n" + " src: url(\"fonts/fontawesome-webfont.eot?#iefix&v=4.0.3\") format(\"embedded-opentype\"), url(\"fonts/fontawesome-webfont.woff?v=4.0.3\") format(\"woff\"), url(\"fonts/fontawesome-webfont.ttf?v=4.0.3\") format(\"truetype\"), url(\"fonts/fontawesome-webfont.svg?v=4.0.3#fontawesomeregular\") format(\"svg\");\n" + " font-weight: normal;\n" + " font-style: normal;\n" + "}\n\n" + ".someclass1 {\n" + " background: url('images/someimage.png') no-repeat;\n" + "}\n\n" + ".someclass2 {\n" + " background: url(\"images/someimage.png\") no-repeat;\n" + "}\n\n" + ".someclass3 {\n" + " background: url(images/someimage.png) no-repeat;\n" + "}"; 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