Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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

/
/
gms

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "<b>(.*?)<\\/b>"; final String string = "<b> GALADRIEL (V.O.)\n" + "</b> (Elvish: subtitled)\n" + " \"I amar prestar sen: han mathon ne nen,\n" + " han mathon ne chae...a han noston ned\n" + " wilith.\"\n" + " (English:)\n" + " The world is changed: I feel it in the\n" + " water, I feel it in the earth, I smell it\n" + " in the air...Much that once was is lost,\n" + " for none now live who remember it.\n\n" + "<b>SUPER: THE LORD OF THE RINGS\n" + "</b>\n" + "<b>EXT. PROLOGUE -- DAY\n" + "</b>\n" + "IMAGE: FLICKERING FIRELIGHT. The NOLDORIN FORGE in EREGION.\n" + "MOLTEN GOLD POURS from the lip of an IRON LADLE.\n\n" + "<b> GALADRIEL (V.O.)\n" + "</b> It began with the forging of the Great\n" + " Rings.\n\n" + "IMAGE: THREE RINGS, each set with a single GEM, are received\n" + "by the HIGH ELVES-GALADRIEL, GIL-GALAD and CIRDAN.\n\n" + "<b> GALADRIEL (V.O.) (CONT'D)\n" + "</b> Three were given to the Elves, immortal,\n" + " wisest...fairest of all beings.\n\n" + "IMAGE: SEVEN RINGS held aloft in triumph by the DWARF LORDS.\n\n" + "<b> GALADRIEL (V.O.) (CONT'D)\n" + "</b> Seven to the Dwarf Lords, great miners\n" + " and craftsmen of the mountain halls.\n\n" + "IMAGE: NINE RINGS clutched tightly by the KINGS OF MEN...as\n" + "if holding-close a precious secret.\n\n" + "<b> GALADRIEL (V.O.) (CONT'D)\n" + "</b> And Nine...nine rings were gifted to the\n" + " race of Men who, above all else, desire\n" + " power.\n" + "<b> (MORE)\n" + "</b>"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.DOTALL); 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