Wubular

Regex quick reference (hover/tap for details)

• [abc]a|b|c

  [abc] matches one of a, b, or c.

  Example: “cab” → matches “c”, “a”, or “b”.

• [^abc]not a|b|c

  [^abc] matches any char except a, b, or c.

  Example: “dog” → “d”, “o”, “g” match; “a” doesn’t.

• [a-z]a..z

  [a-z] matches a lowercase letter.

  Example: “ruby” → every letter matches.

• [a-zA-Z]letter

  [a-zA-Z] matches any letter.

  Example: “v2” → matches “v”, not “2”.

• ^start

  ^ is start of line.

  Example: ^Hi only at the beginning.

• $end

  $ is end of line.

  Example: done$ only at the end.

• \Astr start

  \A is start of string (not just line).

  Example: \AHi matches only once at very start.

• \zstr end

  \z is end of string.

  Example: ok\z matches only at very end.

• .any

  . matches any char (except newline unless m).

  Example: “cat” → “.” can be “c”, “a”, or “t”.

• \sspace

  \s whitespace: space, tab, newline.

  Example: “a b” → matches the space.

• \Snon‑space

  \S any non‑whitespace.

  Example: “ a” → matches “a”, not the space.

• \Rline break

  \R any linebreak.

  Example: “\n” → matches newline.

• \ddigit

  \d digit 0–9.

  Example: “v2” → matches “2”.

• \Dnon‑digit

  \D any non‑digit.

  Example: “v2” → matches “v”, not “2”.

• \wword

  \w letter/number/underscore.

  Example: “a_b” → matches “a”, “_”, “b”.

• \Wnon‑word

  \W not letter/number/_.

  Example: “a-b” → matches “-”.

• \bboundary

  \b word boundary.

  Example: \bcat\b finds “cat” as a whole word.

• (...)capture

  (...) capture group.

  Example: (ab)+ captures repeats of “ab”.

• (a|b)either

  a|b alternation: a or b.

  Example: (cat|dog).

• a?0 or 1 times

  a? zero or one “a”.

  Example: colou?r matches “color”/“colour”.

• a*0+ times

  a* zero or more “a”.

  Example: “ba*” → “b”, “ba”, “baaa”.

• a+1+ times

  a+ one or more “a”.

  Example: “ba+” → “ba”, “baaa” (not “b”).

• a{3}3× times

  a{3} exactly three “a”.

  Example: matches “aaa”.

• a{3,}3+ times

  a{3,} three or more.

  Example: “aaa”, “aaaa”, …

• a{3,6}3–6 times

  a{3,6} between three and six.

  Example: matches “aaa”..“aaaaaa”.

Options (hover/tap for details)

• iignore case

  i makes matches case‑insensitive.

  Example: /cat/i matches “Cat” and “cat”.

• mdot = newline

  m makes . match newline too.

  Example: /a.b/m can span lines.

• xfree‑spacing

  x ignores spaces and # comments in regex.

  Example: /( \d+ ) # number/x

• o#{ } once

  o interpolates #{...} only once.

  Example: /#{Time.now}/o keeps the first value.