Check if value is found in array

Question

I'm trying to check if a certain number is contained within an array.

I have tried using if (value in mines) and var value = this.value; var isMine = mines.indexOf(value);

But neither of these are working as expected. Can anyone explain why? FIDDLE

JS

    var mines = []
while (mines.length < 9){
  var randomnumber=Math.ceil(Math.random() * 30)
  var found=false;
  for(var i=0;i<mines.length;i++){
    if(mines[i]==randomnumber){found=true;break}
  }
  if(!found)mines[mines.length]=randomnumber;
}

$(document).ready(function() {
    $(".blank").click(function() {
        var value = this.value;
        if (value in mines) { 
            $(this).removeClass("blank");
            $(this).addClass("bomb"); 
        } else {
            $(this).removeClass("blank");
            $(this).addClass("safe");
        }
    });
});

HTML

<div class="background">
<table>
    <tr>
    <td colspan="10"><div class="title">title here</div></td>
    </tr>
    <tr>
    <td colspan="10"><div class="info">text here</div></td>
    </tr>
    <tr>
        <td><button class="blank" value="1"></button></td>
        <td><button class="blank" value="2"></button></td>
        <td><button class="blank" value="3"></button></td>
    </tr>
<table>
</div>

Why not you use inArray ? check this : api.jquery.com/jquery.inarray — Bharat Ranpariya
– Bharat Ranpariya, Commented Nov 11, 2014 at 5:40

adeneo · Accepted Answer · 2014-11-11 05:31:48Z

When it's an array you should be using indexOf, but you have two major issues.

Firstly the type has to match. The array has numbers, but the value of an element is always a string.
The easy solution is to parse the value as an integer

var value = parseInt( this.value, 10 );

Secondly, indexOf returns the index, and it will return 0 for the first item in the array, and 0 is falsy, so you have to actually check for -1, which is what indexOf returns if there is no match

if (mines.indexOf(value) != -1) {  ...

FIDDDLE

A little simplified you'd end up with

var mines = [];
while (mines.length < 9){
    var randomnumber = Math.ceil(Math.random() * 30);
    if ( mines.indexOf(randomnumber) == -1 ) 
        mines.push(randomnumber);
}

$(document).ready(function() {
    $(".blank").click(function() {
        var isBomb = mines.indexOf( parseInt( this.value, 10 )) != -1;
        $(this).removeClass('blank').addClass(isBomb ? 'bomb' : 'safe');
    });
});

FIDDLE

huwence · Accepted Answer · 2014-11-11 05:33:52Z

1

var value = +this.value

convert string to integer

answered Nov 11, 2014 at 5:33

huwence

3261 silver badge8 bronze badges

Comments

user2755150 · Accepted Answer · 2014-11-11 05:23:08Z

0

You can just do this:

var myArray = ["one", "two", "three", "four"];
var myString = myArray.join("***") + "***";
var mySubstring = "four";
var inArray = myString.indexOf(mySubstring + "***");

if(inArray >= 0){alert("It's in array");}

answered Nov 11, 2014 at 5:23

user2755150

Comments

Gilsha · Accepted Answer · 2014-11-11 05:24:38Z

0

this.value returns a string. Try this. Updated fiddle

if (mines.indexOf(parseInt(value))!=-1) {  //or  if (parseInt(value) in mines) {
   $(this).removeClass("blank");
   $(this).addClass("bomb"); 
} else {           
   $(this).removeClass("blank");
   $(this).addClass("safe");
}

answered Nov 11, 2014 at 5:24

Gilsha

14.6k3 gold badges36 silver badges48 bronze badges

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