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

/
/
g

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 = "(<li><p><a href=\"https:\\/\\/stat.ethz.ch\\/(m.*r-sig-)(.*)\">.*)"; final String string = "\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-mac\"><code>R-SIG-Mac</code></a>: R Special Interest Group on Mac ports of R</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-db\"><code>R-SIG-DB</code></a>: R SIG on Database Interfaces</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-debian\"><code>R-SIG-Debian</code></a>: R Special Interest Group for Debian ports of R</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-dynamic-models\"><code>R-SIG-dynamic-models</code></a>: Special Interest Group for Dynamic Simulation Models in R</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-ecology\"><code>R-SIG-ecology</code></a>: Using R in ecological data analysis</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-epi\"><code>R-SIG-Epi</code></a>: R for epidemiological data analysis</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-fedora\"><code>R-SIG-Fedora</code></a>: R Special Interest Group for Fedora and Redhat ports of R</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-finance\"><code>R-SIG-Finance</code></a>: Special Interest Group for ‘R in Finance’</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-geo\"><code>R-SIG-Geo</code></a>: R Special Interest Group on using Geographical data and Mapping</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-gr\"><code>R-SIG-gR</code></a>: R SIG on gRaphical models</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-gui\"><code>R-SIG-GUI</code></a>: R Special Interest Group on GUI Development</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-hpc\"><code>R-SIG-HPC</code></a>: R SIG on High-Performance Computing</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-insurance\"><code>R-SIG-Insurance</code></a>: Special Interest Group on using R in actuarial science and insurance</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-jobs\"><code>R-SIG-Jobs</code></a>: R SIG List for Announcements of Jobs where R is used</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-mediawiki\"><code>R-SIG-mediawiki</code></a>: R SIG on the R Extension for Mediawiki</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models\"><code>R-SIG-mixed-models</code></a>: R SIG on Mixed Effect Models, notably lmer() related</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-networks\"><code>R-SIG-networks</code></a>: R SIG for users and developers of network- or graph-related software within R</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-phylo\"><code>R-SIG-phylo</code></a>: R SIG on phylogenetic and comparative methods and analyses</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-qa\"><code>R-SIG-QA</code></a>: R SIG on Quality Assurance &amp; Validation</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-robust\"><code>R-SIG-Robust</code></a>: R SIG on Robust Statistics</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-teaching\"><code>R-SIG-teaching</code></a>: SIG on Teaching Statistics (and more) using R</p></li>\n" + "<li><p><a href=\"https://stat.ethz.ch/mailman/listinfo/r-sig-wiki\"><code>R-SIG-Wiki</code></a>: SIG on the Development of an “R Wiki”</p></li>\n" + "</ul>"; final String subst = ""; final Pattern pattern = Pattern.compile(regex); 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