How can i check if a variable has something in it? I tried checking if a .match() returned null but that wasn't useful for checking with an OR?
All ideas would be gratefully appreciated!
+2
A:
Try this:
var myString = 'I love cheese';
var isMatch = new RegExp(/(cheese|cake)/i).test(myString); //should return true
Rex M
2009-11-01 16:43:24
No, it should not return true. It should return an array of matches.
Guffa
2009-11-01 17:09:30
Thanks, I always mix match and test.
Rex M
2009-11-01 17:35:35
The parentheses here are redundant!
Peter Boughton
2009-11-01 22:10:02
Also worth pointing out that the `i` flag makes it case-insensitive, which may or not be desired depending on the exact needs.
Peter Boughton
2009-11-01 22:10:57
A:
Don't you just want the following?
var result = input.match("cheese") || input.match("cake");
Noldorin
2009-11-01 16:43:26
Using a regex with or, and a single regex, will be more performant than doing do matches (even though they have the same result). Note that I didn't downvote it, but I prefer using the proper regex form.
AlBlue
2009-11-01 17:02:31
@Noldrin Because you don't need `match` where `test` suffices. 1) `match` takes a performance hit by creating an array to hold matched strings (if successful); `test` doesn't. 2) `match` returns array or `null`, not boolean (as `test` does), so you would probably still need to type-convert the result. 3) there's no need to call `match` twice when single regex does it just fine (as in @Gyoshev example). `/cake|cheese/.test(input)` is shorter, simpler and more efficient. Why would you want to use `match` here?
kangax
2009-11-01 17:09:11
@kangax: In reply to: 1. small performance hit. 2. null gets imlicitly converted to `false` and non-null to `true`, so no problem there. 3. using two matches is arguably more readable.
Noldorin
2009-11-01 17:14:03
@Noldorin I don't see implicit type conversion in your example. Mind explaining? Whether performance is relevant or not here is rather subjective, of course. My point is that `test` exists for exactly these kind of purposes, and using match is simply using the wrong tool for the job. I can agree with you about double match being more readable (especially for someone not familiar with regex).
kangax
2009-11-01 17:20:47
@kangax: Perhaps `test` is more appropiate, but my solution is still viable, so I don't see how it deserves a down-vote.
Noldorin
2009-11-01 21:55:31
@Peter: For the "whining"? You obviously have no concept of what a rational discussion is. Might be wise to not to taunt users at least until you have higher rep than them.
Noldorin
2009-11-01 23:20:56
Noldorin, there's a difference between taunting and humour, one that the smiley at the end should make obvious - and in any case SO rep points have no impact on whether or not I'll make a comment. Rex made the same mistake, but he admitted that test was the correct solution and fixed his answer, whilst you're stubbornly sticking to match and are unhappy that someone disagrees with this. \*shrug\*
Peter Boughton
2009-11-01 23:52:21
@Peter: Sorry, but I didn't interpret that as humour. The "sticking tongue out" smiley isn't exactly polite. I referred to rep points mainly to illustrate that you shouldn't assume you know the etiquette of SO. Oh, and it's still not a "mistake".
Noldorin
2009-11-02 10:16:51
Saying this, I don't really want to argue any morpe. Let's agree to disagree. :)
Noldorin
2009-11-02 10:18:12
+5
A:
/cheese|cake/.test(a)
you could add i at the end of the regex if you want to test case-insensitively
Alexander Gyoshev
2009-11-01 16:43:41
+1 not only for `|`, but because `test(...)` is more suitable than `match(...)` in this case.
outis
2009-11-01 16:45:34
+2
A:
As you only got answers involving regular expressions, here is the plain string operation solution:
var hasMatch = input.indexOf('cheese') != -1 || input.indexOf('cake') != -1;
Guffa
2009-11-01 17:01:40
+1
A:
all expressions posted so far would also match "cheeseburger" and "cakewalk". Don't know if this is desirable or not, just in case here's the version that doesn't:
alert(/\b(cheese|cake)\b/i.test("cheese and cake")) // true
alert(/\b(cheese|cake)\b/i.test("cheeseburger and pancake")) // false
stereofrog
2009-11-01 21:55:47