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

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-z]\\[[^\\]]+\\])(.{1}))?(\\s*\\=\\>\\s*)((([a-z]\\[[^\\]]+\\])|([a-z].))(.{1})([A-Z]?)))?(\\s*\\/\\/.*)?"; final String string = "// Алгоритм умножения. Формат ленты: [*]1111#111=*\n" + "// Множество: Q; Начальное значение: q[0]; Конечное значение: q*;\n" + "// Символ пустой ячейки: _; Символ перехода влево: L; Символ перехода вправо: R\n" + "q[0]1 => q[0]1R //2312312323\n" + "q[0]# => q[1]#R\n" + "q[0]* => q[0]*R\n" + "q[1]1 => q[2]aR\n" + "q[2]1 => q[2]1L\n" + "q[2]# => q[3]#L\n" + "q[2]= => q[2]=L\n" + "q[2]a => q[2]aL\n" + "q[3]1 => q[4]aR\n" + "q[3]a => q[3]aL\n" + "q[3]* => q[6]*R\n" + "q[4]1 => q[4]1R\n" + "q[4]# => q[4]#R\n" + "q[4]= => q[4]=R\n" + "q[4]a => q[4]aR\n" + "q[4]* => q[5]1R\n" + "q[5]_ => q[2]*L\n" + "q[6]# => q[7]#R\n" + "q[6]a => q[6]1R\n" + "q[7]1 => q[2]aR\n" + "q[7]= => q[8]=L\n" + "q[7]a => q[7]aR\n" + "q[8]# => q*#\n" + "q[8]a => q[8]1L"; final Pattern pattern = Pattern.compile(regex); 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