Regex Almanac

Regex Almanac

Overview

A high-use Regex collection for the RegexUtil class.

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Regex Between Two Strings

• (?<=(one two)).*?(?=four)
  Example: one two three four → three

• (?<=^).*?(?=$)
  Returns the whole string between start and finish.

• (?<=one).*?(?=four)
  Example: one two three four → two three

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Complete String If

• ^.*(person|server).*$
  Example:
  • This person is cool → This person is cool
  • vanil stick → nothing
  • server one → server one

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Contains None Of These

• ^((?!.*(server|choco).*).)*$
  Example:
  • vanil stick → vanil stick
  • server one → nothing

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Surname (Second Word)

• \\s+[^\\s]+
  Example: mister meeseeks → meeseeks

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Double

• \\d+(\\.\\d+)?
  Example: 20.05

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URL

• [A-Za-z0-9.-]+\\.[A-Za-z]{2,6]

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IPv4

• ([0-9].){4}[0-9]*
  Example: 10.10.10.126

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Phone Number Examples

Example 1

• 0\\d-\\d{7}
  Example:
  • 02-1234567
  • Regex: ^0\\d-\\d{7}$

Example 2

• [0]\\d{9}
  Phone starting with 0 followed by 9 digits.

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Duplicate Word

• \\b(\\w+)\\b(?=.*\\b\\1\\b)
  Example: hadoken hadoken shoryuken → hadoken
• \\b([\\w\\s']+) \\1\\b
  Example: hadoken hadoken shoryuken → hadoken hadoken

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Integer

• [-+]?[0-9]{1,13}

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Name and Surname

• [A-Z][a-z]*\s[A-Z][a-z]*
  Example: Heihachi Mishima

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Negative/Positive Double

• [-+]?[0-9]*[.,][0-9]*
  Example: -30.77

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Full Date

• [0-9]{1,4}/[0-9]{1,2}/[0-9]{1,2} [0-9]{1,2}:[0-9]{1,2}:[0-9]{1,2}
  Example: 2023/09/29 14:30:45

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Timestamp

• [0-9]{1,2}:[0-9]{1,2}:[0-9]{1,2} → 11:52:31
• [0-9]{1,2}:[0-9]{1,2} → 11:42

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Email

• [A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,6]

• ^[a-zA-Z0-9._%+-]+@([a-zA-Z0-9.-]*element[a-zA-Z0-9.-]*)\.[a-zA-Z]{2,}$
  Emails with "element" in them (good for bans).

• ^*@gmail.[a-zA-Z]{2,}$
  Emails from providers like Gmail (good for bans).

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Any String

• ^.+$

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Metacharacters

• + : Contains 1 or more of a character.
• * : Contains 0 or more of a character.
• ? : Contains 0 or 1 of a character.
• (abc)+ : Matches "abc" or "abcabcabc."
• [a-z] : Matches lowercase letters; [ab] matches "a" or "b."
• {5} : Quantifier; e.g., ab{2}c → abbc
• | : OR; e.g., apple|banana matches "apple" or "banana."
• . : Any character; e.g., a.c → "abc," "a1c," "acc."
• ^ : String start.
• $ : String end.

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Fancy Numbers

• (0x)?[0-9a-fA-F]+ : Hexadecimal.
• \\b[01]+\\b : Binary.
• (?<=0.).* : Removes leading zero.
• M{0,3}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3}) : Roman numerals.
• [0-9]{1,3}(,[0-9]{3})*\.[0-9]+ : Numbers with thousand separators.

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First Word in a String

• ^\\w+
  Example: one two three → one

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Last Word in a String

• \\w+$
  Example: one two three four → four

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Number Stripper

• [^\\d]+
  Example: h3llo → h llo