Comparing array value with object

Question

Would be really grateful for any help. Im pretty new to javascript and cant figure out how to solve this problem that I am having. Basically I have 2 arrays. One contains an object with an id value and a corresponding group value. The second array contains only the id. I would like to compare the ids of both the arrays and if they match I would like to extract the corresponding group value.

E.g.

a = [1,2,3,4,5];

b = [{1:group1},{2:group2},{3:group3}];

If id in a matches id in b then print out the id's group value

var a = [];
var b = [];
var c = {};


if (condition) {
   c  = {id:group}
   b.push(c)

}

if (condition) {
   a.push(id)

}

for (var i = 0; i < a.length; i++) {
   //If id value in a exists in b, get id's corresponding group value from b
}

b[a[i]] should work! If it's undefined, a[i] wasn't in b.

Alex Lew
– Alex Lew

2017-06-08 13:42:31 +00:00
Commented Jun 8, 2017 at 13:42 — Alex Lew
– Alex Lew, Commented Jun 8, 2017 at 13:42

Nicolò Boschi · Accepted Answer · 2017-06-08 13:49:43Z

1

function find() {    
   for (var i = 0; i < a.length; i++) {
      for (var j = 0; j < b.length; j++) {
         if (b[j].hasOwnProperty(a[i])) {
            return b[j][a[i]];
         }
      }
   }
}

answered Jun 8, 2017 at 13:49

Nicolò Boschi

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Ravi Gehlot · Accepted Answer · 2017-06-08 14:38:30Z

1

An alternative solution:

<script>
a = [
    1, // index 0
    2, // index 1
    3, // index 2
    4, // index 3
    5  // index 4
];

b = [
    {1:'group1'}, // index [0][1]
    {2:'group2'}, // index [1][2]
    {3:'group3'} // index [2][3]
];

// If id in a matches id in b then print out the id's group value
var i = 1;
for (var key in b) {
    var bKeys = Object.keys(b[key]);

    if(bKeys[0] == a[key]) {
        console.log(b[key][i]);
    }

  i++;
}
</script>

answered Jun 8, 2017 at 14:38

Ravi Gehlot

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