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
Processing...

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 = "# Find the company at the beginning of the line, always:\n" + "^ COMPANY:(?P<company>[^\\s|]+(?:[ ][^\\s|]+)*)\n\n" + "# After COMPANY, any of PERSON or PRODUCT may be matched:\n" + "|\\G [^\\S\\r\\n]*[|][^\\S\\r\\n]*\n" + " PERSON:(?P<person>[^\\s|]+(?:[ ][^\\s|]+)*)\n" + "|\\G [^\\S\\r\\n]*[|][^\\S\\r\\n]*\n" + " PRODUCT:(?P<product>[^\\s|]+(?:[ ][^\\s|]+)*)"; final String string = "COMPANY:Pizza\n" + "COMPANY:Pizza \n" + "COMPANY:Pizza | PERSON:Sid Sanders | PERSON:Louise Lane | PRODUCT:Bananas \n" + "COMPANY:Pizza |PERSON:Sid Sanders | PERSON:Louise Lane| PRODUCT:Bananas\n" + "COMPANY:Pizza| PERSON:Sid Sanders | PERSON:Louise Lane|PRODUCT:Bananas\n" + "COMPANY:Pizza|PERSON:Sid Sanders | PERSON:Louise Lane |PRODUCT:Bananas \n\n" + "COMPANY:Food Heaven\n" + "COMPANY:Food 123 Heaven \n" + "COMPANY:Food Heaven | PRODUCT:Bananas | PERSON:Sid Sanders | PERSON:Louise Lane \n" + "COMPANY:Food Heaven123| PRODUCT:Bananas |PERSON:Sid Sanders | PERSON:Louise Lane\n" + "COMPANY:Food Heaven| PERSON:Sid Sanders | PERSON:Louise Lane | PRODUCT:Bananas \n" + "COMPANY:Food Heaven|PERSON:Sid Sanders| PRODUCT:Bananas | PERSON:Louise Lane\n\n" + "COMPANY:Something Somewhere Anywhere - There\n" + "COMPANY:Something 1 Soöômewhere Anywhere There \n" + "COMPANY:Something 2 Somewhere - Anywhere There | PERSON:Sid Sanders | PRODUCT:Bananas| PERSON:Louise Lane\n" + "COMPANY:Something - Somewhere Anywhere There |PERSON:Sid Sanders| PRODUCT:Bananas | PERSON:Louise Lane\n" + "COMPANY:- Something 3 Somewhere Anywhere There| PERSON:Sid Sanders |PRODUCT:Bananas | PERSON:Louise Lane\n" + "COMPANY:Something Somewhere 4 Anywhere There|PERSON:Sid Sanders | PRODUCT:Bananas | PERSON:Louise Lane\n\n" + "# Should not match:\n" + "|PERSON:Fred Rogers\n" + " | PRODUCT:Mr. Roger's Neighborhood\n\n" + "# Should start matching again:\n" + "COMPANY:Fred Rogers Productions |PERSON:Fred Rogers |PRODUCT:Mr. Roger's Neighborhood\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.COMMENTS); 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