Quantifiers

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Quantifiers indicate numbers of characters or expressions to match.

Types

Characters Meaning
x*

Matches the preceding item x 0 or more times. For example, /bo*/ matches "boooo" in "A ghost booooed" and "b" in "A bird warbled", but nothing in "A goat grunted".

x+

Matches the preceding item x 1 or more times. Equivalent to {1,}. For example, /a+/ matches the "a" in "candy" and all the "a"'s in "caaaaaaandy".

x?

Matches the preceding item x 0 or 1 time. For example, /e?le?/ matches the "el" in "angel" and the "le" in "angle."

If used immediately after any of the quantifiers *, +, ?, or {}, makes the quantifier non-greedy (matching the minimum number of times), as opposed to the default, which is greedy (matching the maximum number of times).

x{n}

Where n is a positive integer. Matches exactly n occurrences of the preceding item x. For example, /a{2}/ doesn't match the "a" in "candy", but it matches all of the "a"'s in "caandy", and the first two "a"'s in "caaandy".

x{n,}

Where n is a positive integer. Matches at least n occurrences of the preceding item x. For example, /a{2,}/ doesn't match the "a" in "candy", but matches all of the a's in "caandy" and in "caaaaaaandy".

x{n,m}

Where n is 0 or a positive integer, m is a positive integer, and m > n. Matches at least n and at most m occurrences of the preceding item x. For example, /a{1,3}/ matches nothing in "cndy", the "a" in "candy", the two "a"'s in "caandy", and the first three "a"'s in "caaaaaaandy". Notice that when matching "caaaaaaandy", the match is "aaa", even though the original string had more "a"'s in it.

x*?
x+?
x??
x{n}?
x{n,}?
x{n,m}?

By default quantifiers like * and + are "greedy", meaning that they try to match as much of the string as possible. The ? character after the quantifier makes the quantifier "non-greedy": meaning that it will stop as soon as it finds a match. For example, given a string like "some <foo> <bar> new </bar> </foo> thing":

  • /<.*>/ will match "<foo> <bar> new </bar> </foo>"
  • /<.*?>/ will match "<foo>"

Examples

 

Browser support

 

See also

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Contributors to this page: chrisdavidmills, mdnwebdocs-bot, jpmedley
Last updated by: chrisdavidmills,