CODEWITHSUNDEEP
javascript
iSidle
iSidle

Reputation: 121

Javascript: How can i check if a array contains certain values

I'm trying to create something that can detect if multiple values are in a array, this is what I tried to use, but that always returns true

row7 = [1, 1, 1, 1, 1, 1, 1, 1];

var field = [row0, row1, row2, row3, row4, row5, row6, row7];
console.log(field[0,1]); // Get the first item in the array


    var needles = [1, 1, 1, 1]
    console.log(needles)
    var haystack = field[0,row7]
    console.log(haystack)

    console.log(contains(haystack,needles));
    function contains(haystack, needles) {

return needles.map(function (needle) { 
    return haystack.indexOf(needle);
}).indexOf(-1) == -1;
}

Case true:

row 7 = [1, 1, 1, 1, 1, 1, 1, 1]

Checked for (four in a row):

needles =  [1, 1, 1, 1]

And false:

 row7 =  [1, 1, 0, 1, 0, 0, 0, 1]

Edit:

Entire array:

/*    Array containing the playing field 8 x 8 

       C0 C1 C2 C3 C4 C5 C6 C7
    R0[0][0][0][0][0][0][0][0]
    R1[0][0][0][0][0][0][0][0]
    R2[0][0][0][0][0][0][0][0] 
    R3[0][0][0][0][0][0][0][0] 
    R4[0][0][0][0][0][0][0][0]
    R5[0][0][0][0][0][0][0][0] 
    R6[0][0][0][0][0][0][0][0] 
    R7[0][0][0][0][0][0][0][0]

*\

    var row0 = [0, 0, 0, 0, 0, 0, 0, 0],
    row1 = [0, 0, 0, 0, 0, 0, 0, 0],
    row2 = [0, 0, 0, 0, 0, 0, 0, 0],
    row3 = [0, 0, 0, 0, 0, 0, 0, 0],
    row4 = [0, 0, 0, 0, 0, 0, 0, 0],
    row5 = [0, 0, 0, 0, 0, 0, 0, 0],
    row6 = [0, 0, 0, 0, 0, 0, 0, 0],
    row7 = [0, 0, 0, 0, 0, 0, 0, 0];

var field = [row0, row1, row2, row3, row4, row5, row6, row7];

Is there any way to achieve this using plain JS?

Thanks in advance.

Upvotes: 1

Views: 175

Answers (3)

Michał Komorowski
Michał Komorowski

Reputation: 6238

I think that the easiest (not the most efficient) solution is to firstly convert both arrays into a string and then check if one string is a sub-string of another one:

function contains(array1, array2) { 
   if(array1 == null || array2 == null)
      return false;

   return array1.toString().contains(array2.toString()); 
}

var row7 = [1, 1, 1, 1, 1, 1, 1, 1];
var needles =  [1, 1, 1, 1];

contains(row7, needles); //returns true

row7 =  [1, 1, 0, 1, 0, 0, 0, 1]

contains(row7, needles); //returns false

UPDATE:

I've just realized that contains function is not supported by all browsers. So it is better to use indexOf i.e. return array1.toString().indexOf(array2.toString()) != -1;

Upvotes: 2

gurvinder372
gurvinder372

Reputation: 68433

change your contains method to

function contains(haystack, needles) 
{
   return haystack.join(",").indexOf(needle.join(",")) != -1;
}

Explanation -

  • do a join of needle to get "1,1,1,1"

  • and the join of haystack to get "1,1,1,1,1,1,1,1"

  • when you do indexOf you will get 0 since needles is contained in haystack

Upvotes: 1

Nina Scholz
Nina Scholz

Reputation: 386756

You can use Array.prototype.every() with an offset for the search.

function check(haystack, needles) {
    var offset = 0;

    while (offset + needles.length <= haystack.length) {
        if (needles.every(function (a, i) {
            return haystack[i + offset] === a;
        })) {
            return true;
        }
        offset++;
    }
    return false;
}

var row7 = [1, 1, 1, 1, 1, 1, 1, 1],
    row8 = [1, 1, 0, 1, 0, 0, 0, 1],
    needles = [1, 1, 1, 1];

document.write(check(row7, needles) + '<br>');
document.write(check(row8, needles) + '<br>');

Upvotes: 1

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