Split array into multiple array's or alternate - Javascript

Question

I have an array

var array = ['123.456789,123.1','456.7890123,234.1','789.0123456,345.1'];

The outcome I'm looking for is

var array1 = [123.456789,456.7890123,789.0123456];
var array2 = [123.1,234.1,345.1];

What's best practice for doing this? I've been looking at .split(""); but would like to know the best way to approach it.

Thanks in advance Mach

letiagoalves · Answer 1 · 2013-02-21T09:55:17.110

3

I think that you should go with split function. Try this or see this DEMO:

var array = ['123.456789,123.1','456.7890123,234.1','789.0123456,345.1'];
var array1 = [], array2 = [];

for(var i=0; i<array.length; i++){
   array1[i] = array[i].split(",")[0];
   array2[i] = array[i].split(",")[1];
}

edited Feb 21 '13 at 09:55

answered Feb 21 '13 at 09:37

letiagoalves

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[Don't use `var i in array` syntax to iterate arrays](http://stackoverflow.com/questions/500504/javascript-for-in-with-arrays). – Ja͢ck Feb 21 '13 at 09:46
@Jack what do you sugest? `for(var i=0; i – letiagoalves Feb 21 '13 at 09:48
1

Yep, that would be better :) you can also cache the array length in a local variable (micro optimization though). – Ja͢ck Feb 21 '13 at 10:02

score 3 · Accepted Answer · answered Feb 21 '13 at 09:39

3

var arr = ["123.456789,123.1","456.7890123,234.1","789.0123456,345.1"];

var array1 = [],
    array2 = arr.map(function(e) {
        e = e.split(",");
        array1.push(+e[0]);
        return +e[1];
    });

console.log(array1, array2);

answered Feb 21 '13 at 09:39

VisioN

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why the plus sign in **+e[0]**? Is it the same as a cast? – letiagoalves Feb 21 '13 at 09:56
@letiagoalves Yep, it's a shorcut for `Number(e[0])`. – VisioN Feb 21 '13 at 10:06

score 1 · Answer 3 · answered Feb 21 '13 at 09:40

1

Basically you should iterate over the array and for each item you split the string into two parts, based on the comma. Each part goes into their respective array.

If Array.forEach() is allowed:

var a1 = [], a2 = [];

array.forEach(function(item) {
  var parts = item.split(',');
  a1.push(+parts[0]);
  a2.push(+parts[1]);
}

Otherwise:

var a1 = [], a2 = [];

for (var i = 0, item; item = array[i]; ++i) {
  var parts = item.split(',');
  a1.push(+parts[0]);
  a2.push(+parts[1]);
}

answered Feb 21 '13 at 09:40

Ja͢ck

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In your case it is better to use `Array.forEach`. – VisioN Feb 21 '13 at 09:41
@VisioN Don't remember using that before ... ah yes, that's a lot better :) – Ja͢ck Feb 21 '13 at 09:41

Split array into multiple array's or alternate - Javascript

3 Answers3