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

/
/
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 = "(?=(?=(?'a'[\\s\\S]*))(?<!'b'<p\\b[^>][\\s\\S]color[\\s\\S]:[\\s\\S]black[^>][\\s\\S]>[\\s\\S]<span\\b[^>][\\s\\S]>[\\s\\S])(?<!<span\\b[^>][\\s\\S]color[\\s\\S]:[\\s\\S]black[^>][\\s\\S]>[\\s\\S])_(?=\\k'a'\\z)|(?<=(?=x^|(?<!&b))[\\s\\S]))<code\\s*style=\"background-color:\\s*transparent;\">"; final String string = "<html>\n" + "<p style=\"font-family: &quot;verdana&quot;; font-size: 18px; color: black; line-height: 18px; text-align: justify; font-style: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; background-color: cyan;\"><span style=\"font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;;\"><code style=\"background-color: transparent;\"><b>some text here</b></code></span></p>\n" + "<span><span style=\"font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;; background-color: cyan;\"><code style=\"background-color: transparent;\"><b>some text here</b></code></span>\n\n" + "<code style=\"background-color: transparent;\">\n\n" + "<p style=\"font-family: &quot;verdana&quot;; font-size: 18px; color: cyan; line-height: 18px; text-align: justify; font-style: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; background-color: cyan;\"><span style=\"color: black; font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;;\"><code style=\"background-color: transparent;\"><b>some text here</b></code></span></p>\n" + "<span><span style=\"font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;; background-color: cyan;\"><code style=\"background-color: transparent;\"><b>some text here</b></code></span>\n" + "<p style=\"font-family: &quot;verdana&quot;; font-size: 18px; color: cyan; line-height: 18px; text-align: justify; font-style: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; background-color: navy;\"><span style=\"font-size: 13.5pt; font-family: &quot;Verdana&quot;,&quot;sans-serif&quot;;\"><code style=\"background-color: transparent;\"><b>some text here</b></code></span></p>\n" + "</html>"; 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