Regular Expressions 101

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  • Unit Tests (21)

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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 = "^((((\\d+,)+\\d+|(\\d+(\\/|-|#)\\d+)|\\d+L?|\\*(\\/\\d+)?|L(-\\d+)?|\\?|[A-Z]{3}(-[A-Z]{3})?) ?){5,7})|(@(annually|yearly|monthly|weekly|daily|hourly|reboot))|(@every (\\d+(ns|us|µs|ms|s|m|h))+)$"; final String string = "# cron\n" + "0 0 1 1 * 1\n" + "0 0 1 1 * 1,2\n" + "0 0 1 1 * 1,2,3\n" + "0 0 1 * * 1/4\n" + "0 0 * * 0 1-4\n" + "0 0 * * * 2/4\n" + "0 * * * * *\n\n" + "# variations\n" + "10 12 * * 1,2,3,4,5\n" + "* 10 12 * * 1,2,3,4,5\n" + "* */5 * * * *\n\n" + "*/4 */4 */4 * * *\n\n" + "# At 12:00 pm (noon) every day during the year 2017:\n" + "0 0 12 * * ? 2017\n" + "# Every 5 minutes starting at 1 pm and ending on 1:55 pm and then starting at 6 pm and ending at 6:55 pm, every day:\n" + "0 0/5 13,18 * * ?\n" + "# Every minute starting at 1 pm and ending on 1:05 pm, every day:\n" + "0 0-5 13 * * ?\n" + "# At 1:15 pm and 1:45 pm every Tuesday in the month of June:\n" + "0 15,45 13 ? 6 Tue\n" + "# At 9:30 am every Monday, Tuesday, Wednesday, Thursday, and Friday:\n" + "0 30 9 ? * MON-FRI\n" + "# At 9:30 am on 15th day of every month:\n" + "0 30 9 15 * ?\n" + "# At 6 pm on the last day of every month:\n" + "0 0 18 L * ?\n" + "# At 6 pm on the 3rd to last day of every month:\n" + "0 0 18 L-3 * ?\n" + "# At 10:30 am on the last Thursday of every month:\n" + "0 30 10 ? * 5L\n" + "# At 6 pm on the last Friday of every month during the years 2015, 2016 and 2017:\n" + "0 0 18 ? * 6L 2015-2017\n" + "# At 10 am on the third Monday of every month:\n" + "0 0 10 ? * 2#3\n" + "# At 12 am midnight on every day for five days starting on the 10th day of the month:\n" + "0 0 0 10/5 * ?\n\n" + "# more\n" + "0 0 12 * * ?\n" + "0 15 10 ? * *\n" + "0 15 10 * * ?\n" + "0 15 10 * * ? *\n" + "0 15 10 * * ? 2005\n" + "0 * 14 * * ?\n" + "0 0/5 14 * * ?\n" + "0 0/5 14,18 * * ?\n" + "0 0-5 14 * * ?\n" + "0 10,44 14 ? 3 WED\n" + "0 15 10 ? * MON-FRI\n" + "0 15 10 15 * ?\n" + "0 15 10 ? * 6L\n" + "0 15 10 ? * 6L 2002-2005\n" + "0 15 10 ? * 6#3\n" + "0 0 12 1/5 * ?\n" + "0 11 11 11 11 ?\n\n" + "# predefined\n" + "@annually\n" + "@yearly\n" + "@monthly\n" + "@weekly\n" + "@daily\n" + "@hourly\n" + "@reboot\n\n" + "# every\n" + "@every 5s\n" + "@every 20h30m\n\n" + "#individual forms\n" + "1,2,3\n" + "1,2\n" + "1/2\n" + "1-2\n" + "1\n" + "*\n" + "0\n" + "*/4\n" + "6#3\n" + "L\n" + "5L\n" + "L-2\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