Regular Expressions 101

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  • Substitution
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  • Unit Tests (9)

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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 = "(?x)\n" + "(\\/\\/[ \\t]*)\n" + "(\n" + "\\[(?:\n" + " (?:[-]?\\d+(?:.\\d)*)(?:[ \\t]*:[ \\t]*-?\\d+(?:.\\d)*){0,2} \n" + " |\n" + " (?:(?:[^:,]+:)?[^:,]+,)*(?:(?:[^:,]+:)?[^:,]+)\n" + ")\\]\n" + ")\n" + "[ \\t]*$\\n?"; final String string = "\n" + "// Internal Diameter\n" + "innerWidth = 11.733333; // [40]\n" + "innerWidth = 11.733333; \n" + "// \n" + "[Invalid: thing]\n" + "height = 14;\n" + "wallWidth = 2;\n\n" + "//#region [Options] Advanced\n\n" + "/* [Advanced Options] */\n" + "enable_sloped_walls =true; // [10:20]\n" + "outerWidth_delta = 0.2;\n\n" + "enable_sloped_walls_inner = true;\n" + "innerDelta = -1;\n\n" + "rounded_top = true;\n" + "rounding_top = nothing * 5;\n\n" + "rounded_bottom = false;\n" + "rounding_bottom = 1.5;"; final String subst = ""; 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