How to find if a value matches one of the values from an array in Javascript

Question

FYI: this is for a simple quiz with just a single input field for each answer.

I have the following Javascript if statement to check if the value entered into an input field is correct (in this case, if the value entered is 'england').

$('input').keyup(function () {
    if ($(this).val().toLowerCase() == 'england') {
        //Stuff
    } else {
        //Other Stuff
    };
});

However, I want to allow for alternative spellings, so I need a few possible answers for each question - it seems sensible to use an array for this as so...

var ans1 = new Array();
ans1[0] = "England";
ans1[1] = "Englund";
ans1[2] = "Ingland";

How can I change my if statement to say 'if the input field value equals any of those values from the array, then do the following'?

Any help would be greatly appreciated! Thank you.

palaѕн · Accepted Answer · 2013-11-05T10:42:57.630

6

You can do this using .inArray():

if ($.inArray($(this).val(), ans1) > -1) {
    //Stuff
}

Here, the code $.inArray($(this).val(), ans1) will search for a specified value for example England within an array ans1 and return its index (or -1 if not found).

UPDATE

For case-sensitive search:

First enter all the values in the array in Lower Case
Next use the code below:-

JS:

if ($.inArray($(this).val().toLowerCase(), ans1) > -1) {
    //Stuff
}

edited Nov 05 '13 at 10:42

answered Nov 05 '13 at 10:30

palaѕн

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This worked, but only when removing the .toLowerCase() function, which means if users enter the value in capitals then it will not accept the answer. Almost. – user2586455 Nov 05 '13 at 10:40
@user2586455: I have updated the answer as you pointed out! – palaѕн Nov 05 '13 at 10:44
1

Excellent! So it was my bad for entering the array values with capitals. Thank you for your help. – user2586455 Nov 05 '13 at 10:47

score 4 · Answer 2 · edited Nov 05 '13 at 10:38

4

You can use the 'indexOf' method of the array, this will return -1 if the value doesn't exist in the array:

//if answer is in array
if(array.indexOf(answer) != -1){
    //do stuff
}else{
  //do stuff
}

edited Nov 05 '13 at 10:38

georg

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answered Nov 05 '13 at 10:32

James

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I'm sure this makes perfect sense to many, but the answer/code wasn't specific enough for me. Thanks anyway! – user2586455 Nov 05 '13 at 10:49

Anton · Answer 3 · 2013-11-05T10:47:04.877

3

Try this

if(this.value.match(/^(England|Englund|Ingland)$/i))

using regex and gi modifier for case insensitive

edited Nov 05 '13 at 10:47

answered Nov 05 '13 at 10:32

Anton

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`this.value` == `Inglandia` ? – georg Nov 05 '13 at 10:36
@thg435 Inglandia? :P – Anton Nov 05 '13 at 10:38
Exactly! And now 7 more chars so SO will let me post. – Kong Nov 05 '13 at 10:38
1

I think thg435's point is that your regex should be `/^(England|Englund|Ingland)$/i`. – nnnnnn Nov 05 '13 at 10:40
Ah i see now what you mean, and thanks @nnnnnn – Anton Nov 05 '13 at 10:41
@nnnnnn: `Englundia`? ;] – georg Nov 05 '13 at 10:41
@thg435 - Ha, yes, I edited my comment to fix that right before I saw your latest one... (+1 to Anton on the edited version of the answer.) – nnnnnn Nov 05 '13 at 10:42
The point being that you can do this with a very simple regex; OP can maybe figure the spelling? – Kong Nov 05 '13 at 10:42
@nnnnnn: damn you're fast, cowboy! Now let's wait for the OP to fix this `length>0` thing... – georg Nov 05 '13 at 10:45
there, thanks thg435 and nnnnnn i'm not that great with regex ^^ – Anton Nov 05 '13 at 10:47
2

Looks fine now, kudos for improving! – georg Nov 05 '13 at 10:53

score 0 · Answer 4 · answered Nov 05 '13 at 10:31

Do like this

$('input').keyup(function () {

var ans1 = new Array();
ans1[0] = "England";
ans1[1] = "Englund";
ans1[2] = "Ingland";
for(int i=0;i<ans1.length;i++)
{

    if ($(this).val().toLowerCase() ==ans1[i]) {
        //Stuff
    } else {
        //Other Stuff
    };
}
});

score 0 · Answer 5 · answered Nov 05 '13 at 10:31

0

Perhaps you may consider checking each element of the array like that:

var ans1 = new Array();
ans1[0] = "England";
ans1[1] = "Englund";
ans1[2] = "Ingland";

$('input').keyup(function () {
    for (var i = 0; i < ans1.length; i++) {
       if ($(this).val().toLowerCase() == ans1[i]) {
        //Stuff
         } else {
        //Other Stuff
       };
    }
});

Not the most beautiful solution, but it should work.

answered Nov 05 '13 at 10:31

briosheje

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You could have used hashmap instead or .inArray() – user3566643 Aug 08 '14 at 17:10
indeed, but it was already proposed in another solution :) – briosheje Aug 09 '14 at 07:42

Igl3 · Answer 6 · 2013-11-05T10:38:17.073

jQuery offers $.inArray:

var found = $.inArray('specialword', words) > -1;

Note that inArray returns the index of the element found, so 0 indicates the element is the first in the array. -1 indicates the element was not found.

put your spellings in an array like this:

words: [
    "England"
    "Inglund"
    "Ingland"
]

Found will be true if the word was found.

If you want the index of the matched word delete > -1 from the line.

Your code would be like this:

$('input').keyup(function () {
    var found = $.inArray($(this).val(), words);
    found > -1 ? //Stuff : //otherStuff;

});

How to find if a value matches one of the values from an array in Javascript

6 Answers6