Why String.match() method returns multiple values?

Question

I've got the following string, defined in my Javascript code:

var s = "10px solid #101010";

Now, I want to get only the numeric initial part. For this purporse, I tried the following:

s.match(/^([0-9]+)/g);

It works like a charm, and the result was ['10'].

After this test, I also tried to remove the g modifier, as follows:

s.match(/^([0-9]+)/);

I expected the same result, but I was wrong. The result is an array with two solutions: ['10', '10'].

Can someone explain me why? What is the meaning of the last element of the array, in the second case?

Good question, which actually already has a really good answer here: http://stackoverflow.com/questions/18577704/why-capturing-group-results-in-double-matches-regex — Robin, May 22 '14 at 13:56
^^ The accepted answer actually does have a very good explanation of this, seems like a duplicate. — adeneo, May 22 '14 at 13:59
If I have not clear the concept of "capturing group", the answer of question you quote is not adequate (in my opinion)... — Vito Gentile, May 22 '14 at 14:03
@VitoShadow I guess you actually wanted to put the `+` into the capturing group like `/^([0-9]+)/` otherwise the group would only capture single digits — devnull69, May 22 '14 at 14:10
Also ... the result of removing `g` is `['10', '0']` rather than `['10', '10']` ... at least in my Chrome — devnull69, May 22 '14 at 14:12
just get rid of the brackets ;-) ... `s.match(/^[0-9]+/g);` works like your first example and `s.match(/^[0-9]+/);` doesn't give the duplicate ... you don't even need to specify the start (`^`), as it's the first match `s.match(/[0-9]+/);` ... and if you like, you could use `\d` instead of [0-9] `s.match(/\d+/);` — imma, May 22 '14 at 16:21

score -2 · Answer 1 · edited May 22 '14 at 14:09

-2

'/g' returns all matched ones, It wont stop at first matching point

'g '- Perform a global match (find all matches rather than stopping after the first match)

edited May 22 '14 at 14:09

Antonio E.

answered May 22 '14 at 13:56

malkam

1 Answers1