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

/
/
gi

Test String

Substitution

Processing...

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*(logo|image|screenshot|race_logo|track map)\\s*=\\s*)(File:|Image:)?([^\\[\\||<\\n]*)((\\|\\s*\\d{1,4}px(\\?)?|\\|\\s*thumb))((\\|\\s*\\d{1,4}px(\\?)?|\\|\\s*thumb))?(?(?=\\|[A-z]*\\s*=)|(?(?=\\|(\\w*\\W*)*)(\\|[^\\|\\n]*)?)?)"; final String string = "| image = [[File:Central Asia (orthographic projection).svg|200px|Map of Central Asia]]\n\n" + "|Image=|150px? \n\n" + "}}]] &ndash; [[Template:POTD/2012-06-09|{{POTD texttitle\n" + "|image=Jack-in-cube solid model, light background.gif\n" + "|thumb=Jack-in-cube solid model, light background frame.png\n" + "|size=180\n\n" + "|name = Reggae\n" + "| Image = File:Bob-Marley.jpg|thumb|231px|\n" + "| caption = Popular reggae artist [[Bob Marley]] in 1980\n\n" + "{{Infobox officeholder\n" + "|image = Karenskiy AF 1917.jpg|230px\n" + "|nationality = Russian\n\n" + "{{Infobox officeholder\n" + "|image = Karenskiy AF 1917.jpg|230px|thumb\n" + "|nationality = Russian\n\n" + "{{Infobox officeholder\n" + "|image = Karenskiy AF 1917.jpg|thumb\n" + "|nationality = Russian\n\n" + "{{Infobox officeholder\n" + "|image = Karenskiy AF 1917.jpg|230px|nationality = Russian\n\n" + "|country=IND\n" + "|image= National Highway 2 (India).png|300px|Road map of India with NH 19 highlighted in solid blue color\n" + "|type=NH\n\n" + "|image = File:April 14, 2012 Marquette, Kansas EF4 tornado.JPG|309px\n\n" + "{{Infobox football club |\n" + " clubname = Slovácko |\n" + " image = Image:1FC Slovacko.png|150px|Logo |\n" + " fullname = 1. FC Slovácko A.S. |\n\n" + "| image = <imagemap>\n" + "File:Primates - some families.jpg|300px"; final String subst = "$1$4"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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