Regular Expressions 101

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  • Unit Tests (10)

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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

/
/
gmxX

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "(\\$)\n" + "# Regexp for textmate dynamic variables \n" + "#TM_(\n" + "# BUNDLE_SUPPORT|COMMENT_(?:END|MODE|START)|CURRENT_(?:LINE|WORD)|DIRECTORY|FILE(?:NAME|PATH)|\n" + "# LINE_(?:INDEX|NUMBER)|PROJECT_DIRECTORY|SCOPE|SELECTED_(?:FILE[S]?|TEXT)|SOFT_TABS|SUPPORT_PATH|TAB_SIZE\n" + "#)\n" + "(?:\n" + "# BASIC\n" + " # BASIC: Variable name, no brackets\n" + " (?:(TM_[A-Z]+(?:_[A-Z]+)*)|([\\d]))(?!\\{)\n" + "|\n" + "# BRACKETED\n" + " ([\\{])\n" + " # BRACKETED: Variable name\n" + " (?:(TM_[A-Z]+(?:_[A-Z]+)*)|([\\d]))\n" + " # BRACKETED: Post variable name expression\n" + " (?:\n" + " # Default keyword, single\n" + " ([:].+?(?=[\\}]))\n" + " |\n" + " # Default keyword, options\n" + " ([\\|].+?[\\|](?=[\\}]))\n" + " |\n" + " # Regular expression\n" + " (?:\n" + " ([\\/])\n" + " (.+?(?=\\/))\n" + " ([\\/])\n" + " (.+?(?=\\/))\n" + " ([\\/])\n" + " # Flags\n" + " # Not sure how to validate fully without back references?\n" + " ([imx]{3})\n" + " (?=\\})\n" + " )\n" + " |\n" + " (?:\n" + " ([\\/])\n" + " ([^\\/\\}]+?)\n" + " (\n" + " (?<![\\\\]{2})\n" + " [\\/]\n" + " )\n" + " ([^\\/\\}]+?)\n" + " (\n" + " (?<![\\\\]{2})\n" + " [\\/]\n" + " )\n" + " # Flags\n" + " # Not sure how to validate fully without back references?\n" + " ([imx]{3})\n" + " )\n" + " | \n" + " # Match to bracket\n" + " (.+?(?=[\\}]))?\n" + " )?\n" + " ([\\}])\n" + ")"; final String string = "~~ Number Variables ~~~~~~~~~\n" + "Basic\n" + "\"$0\"\n" + "Bracketed\n" + "\"${1} \n" + "Default Value\n" + "\"${2:default}\"\n" + "Default Values\n" + "\"${3|defaultA,defaultB|}\"\n" + "Regex Replace\n" + "\"${4/find/replace/gmi}\"\n\n" + "~~ Dynamic Variables ~~~~~~~~\n" + "Basic\n" + "\"$TM_SELECTION_START\"\n" + "Bracketed\n" + "\"${TM_SELECTION_END}\"\n" + "Default Value\n" + "\"${TM_SELECTED_FILE:default}\"\n" + "Default Values\n" + "\"${TM_SELECTED_TEXT|defaultA,defaultB|}\"\n" + "Regex Replace\n" + "\"${TM_SELECTED_FILES/find/replace/gmi}\"\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