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"
"
gm

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*(?:([A-Z][a-z]+(?:\\s[A-Z][a-z]+)?))?\\s*=?\\s*.*?([\\w.]+@[\\w.-]+)"; final String string = " > Begin forwarded message:\n" + ">=20\n" + "> Date: December 20, 2013 at 11:32:39 AM GMT-3\n" + "> Subject: My dummy subject\n" + "> From: Charlie Brown <aaa@aa-aaa.com>\n" + "> To: maria.brown@aaa.com, George Washington <george@washington.com>, =\n" + "thomas.jefferson@aaa.com, thomas.alva.edison@aaa.com, Juan =\n" + "<juan@aaa.com>, Alan <alan@aaa.com>, Alec <alec@aaa.com>, =\n" + "Alejandro <aaa@aaa.com>, Alex <aaa@planeas.com>, Andrea =\n" + "<andrea.mery@thomsen.cl>, Andrea <andrea.22@aaa.com>, Andres =\n" + "<andres@aaa.com>, Andres <avaldivieso@aaa.com>\n" + "> Hi,\n" + "> Please reply ASAP with your RSVP\n" + "> Bye"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); 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