Can I do this with JS array?

Question

I want to create an array called currentArray, but I want its contents to be made up from a different array. Basically a copy. However, I want to affect which array is being copied into currentArray with a variable (int).

Here's what I mean:

function region(number)
{
        var regionArray1 = [1093, 1276, 436, 541];
        var regionArray2 = [563, 747, 310, 423, 744, 947, 601, 715];

        var currentArray = (regionArray+number)[]; 
}

number will be either 1 or 2. What is the correct way to do this, if I can? I've also tried var currentArray = ("regionArray"+number)[]; but that doesn't seem to be the right way either.

RoToRa · Accepted Answer · 2011-04-01 13:40:38Z

5

The "best" way would be to make regionArray an array of arrays (or an Object of arrays):

function region(number)
{
    var regionArray = {
                        "1": [1093, 1276, 436, 541], 
                        "2": [563, 747, 310, 423, 744, 947, 601, 715]
                      };

    var currentArray = regionArray[number]; 
}

answered Apr 1, 2011 at 13:40

RoToRa

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1 Comment

Šime Vidas Over a year ago

No need for the object keys overhead - an array of array is good enough.

sunn0 · Accepted Answer · 2011-04-01 13:41:35Z

2

I would use a two dimensional array:

function region(number) {
    var regionArrays = [
        [1093, 1276, 436, 541],
        [563, 747, 310, 423, 744, 947, 601, 715]
    ];
    var currentArray = regionArrays[number - 1];

}

answered Apr 1, 2011 at 13:41

sunn0

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1 Comment

Briz Over a year ago

I got a lot of great answers, but I'm picking this one because not only is it a correct answer but he also noticed that I said that the number variable would be 1 or 2. ;)

Šime Vidas · Accepted Answer · 2011-04-01 13:41:41Z

2

function region(i) {
    var regionArray = [
        [1093, 1276, 436, 541],
        [563, 747, 310, 423, 744, 947, 601, 715]
    ];

    var currentArray = regionArray[i];
}

answered Apr 1, 2011 at 13:41

Šime Vidas

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Comments

Mikhail · Accepted Answer · 2011-04-01 13:39:12Z

0

You should use a switch/case. eval should not be used in cases where you know all the information that needs to be executed.

function region(n) {
    // define arrays ...
    switch(n) {
        case 1 : currentArray = regionArray1; break;
        case 2 : currentArray = regionArray3; break;
    }
}

If this extends to more than 2 you can have an array of arrays and simply assign currentArray = arrayChoices[n];

answered Apr 1, 2011 at 13:39

Mikhail

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Comments

BiAiB · Accepted Answer · 2011-04-01 13:49:47Z

0

why not this :

function region(number)
{
        var regionArray = [];
        regionArray[0] = [1093, 1276, 436, 541];
        regionArray[1] = [563, 747, 310, 423, 744, 947, 601, 715];

        var currentArray = regionArray[ number ]; 
}

edited Apr 1, 2011 at 13:49

answered Apr 1, 2011 at 13:40

BiAiB

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1 Comment

Šime Vidas Over a year ago

This is syntactically invalid.

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