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When I run
/(a)/g.exec('a a a ').length I get
2 but I thought it should return
3 because there are 3 as in the string, not 2!
Why is that?
I want to be able to search for all occurances of a string in RegEx and iterate over them.
FWIW: I'm using node.js
836
Difference between test () and exec () methods in JavascriptTest tests for matches and returns booleans while exec captures groups and matches the regex to the input. If you only need to test an input string to match a regular expression, RegExp. test is most appropriate.
JavaScript RegExp exec() The exec() method tests for a match in a string. If it finds a match, it returns a result array, otherwise it returns null.
match(regexp) finds matches for regexp in the string str . If the regexp has flag g , then it returns an array of all matches as strings, without capturing groups and other details. If there are no matches, no matter if there's flag g or not, null is returned.
The exec() Method in JavaScript is used to test for match in a string. If there is a match this method returns the first match else it returns NULL. Syntax: RegExpObject.exec(str) Where str is the string to be searched.
exec() is returning only the set of captures for the first match, not the set of matches as you expect. So what you're really seeing is $0 (the entire match, "a") and $1 (the first capture)--i.e. an array of length 2. exec() meanwhile is designed so that you can call it again to get the captures for the next match. From MDN:
If your regular expression uses the "g" flag, you can use the exec method multiple times to find successive matches in the same string. When you do so, the search starts at the substring of str specified by the regular expression's lastIndex property (test will also advance the lastIndex property).
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