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 = "^\\s+$"; final String string = "\n" + " \n" + " \n" + "General Information\n" + " \n" + " \n" + " Brand: \n" + " Whirlpool \n" + " \n" + " \n" + " Model name: \n" + " PACW9HP \n" + " \n" + " \n" + " Type: \n" + " On/Off \n" + " \n" + " \n" + " Construction Type: \n" + " Free-Standing \n" + " \n" + " \n" + " Number of Speeds: \n" + " 7 \n" + " \n" + " \n" + " \n" + " \n" + "Mode\n" + " \n" + " \n" + " Cooling: \n" + " Yes \n" + " \n" + " \n" + " Heating: \n" + " Yes \n" + " \n" + " \n" + " Antibacterial Filters: \n" + " Yes \n" + " \n" + " \n" + " Ionization: \n" + " Yes \n" + " \n" + " \n" + " Sleep Function: \n" + " Yes \n" + " \n" + " \n" + " \n" + " \n" + "Conditioner Features\n" + " \n" + " \n" + " Recommended Area: \n" + " 25 - 30 m² \n" + " \n" + " \n" + " Capacity Cooling (BTU): \n" + " 9000 \n" + " \n" + " \n" + " Capacity Heating (BTU): \n" + " 8500 \n" + " \n" + " \n" + " Capacity Cooling (W): \n" + " 3000 \n" + " \n" + " \n" + " Capacity Heating (W): \n" + " 2000 \n" + " \n" + " \n" + " Air Flow: \n" + " 350 m³/h \n" + " \n" + " \n" + " Indoor Noise Level: \n" + " 65 \n" + " \n" + " \n" + " HEPA Filter: \n" + " Yes \n" + " \n" + " \n" + " \n" + " \n" + "Compressor\n" + " \n" + " \n" + " Refrigerant: \n" + " R410A \n" + " \n" + " \n" + " Type of Compressor: \n" + " Rotary \n" + " \n" + " \n" + " \n" + " \n" + "Energy Rating\n" + " \n" + " \n" + " Energy Efficiency Class: \n" + " A+ \n" + " \n" + " \n" + " \n" + " \n" + "Remote Control\n" + " \n" + " \n" + " Remote Control: \n" + " Yes \n" + " \n" + " \n" + " Timer on / off: \n" + " Yes \n" + " \n" + " \n" + " \n" + " \n" + "Power\n" + " \n" + " \n" + " Power from: \n" + " Network \n" + " \n" + " \n" + " Voltage: \n" + " 200-240 V \n" + " \n" + " \n" + " Cord Length: \n" + " 1.2 m \n" + " \n" + " \n" + " \n" + " \n" + "Color\n" + " \n" + " \n" + " Color: \n" + " White \n" + " \n" + " \n" + " \n" + " \n" + "Dimensions\n" + " \n" + " \n" + " Dimensions (W x H x D): \n" + " 448 x 743 x 400 mm \n" + " \n" + " \n" + " \n" + " \n" + "Weight\n" + " \n" + " \n" + " Weight: \n" + " 31 kg \n" + " \n" + " \n" + " \n" + " \n" + "Warranty\n" + " \n" + " \n" + " Warranty: \n" + " 36 Months \n" + " \n" + " \n\n"; 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