CODEWITHSUNDEEP
javascript
supercoolville
supercoolville

Reputation: 9086

Combine 2 arrays into a multidimensional array?

This is based on my last question.

I have these arrays:

var array1 = new Array ("Pepsi", "Coke", "Juice", "Water");
var array2 = new Array ("35",    "17",   "21",    "99");

And I want to combine them to form a multidimensional array like this: 

[
    ["Pepsi","35"]
    ["Coke", "17"]
    ["Juice","21"]
    ["Water","99"]
]

I tried this script:

Values=[];

for (i = 0; i < array1.length; i++) {
    Values[i] = Array(array1[i], array2[i]);
}

But it gave a result like this (correct values, incorrect names):

[
    ["a","35"]
    ["c","17"]
    ["E","21"]
    ["I","99"]
]

Upvotes: 8

Views: 11883

Answers (2)

cliffs of insanity
cliffs of insanity

Reputation: 3694

You can use .map() on Arrays.

var Values = array1.map(function(v,i) {
    return [v, array2[i]];
});

See the MDN shim for older browsers.

live demo: http://jsfiddle.net/D9rjf/

If you're going to do this operation quite a bit, you could make a reusable function.

In this example, I extended Array.prototype, but that's not necessary if you don't like that.

Array.prototype.combine = function(arr) {
    return this.map(function(v,i) {
        return [v, arr[i]];
    });
};

var Values = array1.combine(array2);

live demo: http://jsfiddle.net/D9rjf/1/

Upvotes: 13

Sampson
Sampson

Reputation: 268324

var array1 = ["Pepsi", "Coke", "Juice", "Water"],
    array2 = ["35", "17", "21", "99"],
    result = [], i = -1;

while ( array1[++i] ) { 
  result.push( [ array1[i], array2[i] ] );
}

As written, this solution assumes you will only ever be using strings. As @ajax333221 has pointed out in the comments below, this would cause problems if you were to involve boolean or int values into this solution. As such, I'd like to propose an improvement that will accomplish your goals, while not tripping over difficult values and types:

var array1 = [false, 0, "Juice", -1],
    array2 = ["35", "17", "21", "99"],
    result = [];

for ( var i = 0; i < array1.length; i++ ) {
  result.push( [ array1[i], array2[i] ] );
}

Upvotes: 18

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