make variable from variable javascript

Question

i am trying to add data to an array where part of the array name is a variable.

if that makes sense?

this is my coding, i think its something to do with the ["charts"[d]] part but nothing is being added to the arrays

    var 
    charts0 = [],
    charts1 = [],
    charts2 = [],
    charts3 = []
    var newdata = data.split("|");
    var newdates = dates.split(",");
    for (i = 0; i < newdates.length; i++) { 
        for (d = 0; d < newdata.length; d++) { 
        var dataparts = newdata[d].split(",");
        ["charts"[d]].push({x: newdates[i], y: dataparts[i+1]});

        }
    }

It cannot be done (exept for using eval, which you shouldn't). — Bas Slagter
– Bas Slagter, Commented Nov 22, 2015 at 12:17
If you want to name something, just add one extra layer of array on top. — Karoly Horvath
– Karoly Horvath, Commented Nov 22, 2015 at 12:17

Ben Aston · Accepted Answer · 2015-11-22 12:47:24Z

3

Use an object literal as an associative array.

var charts = {
  charts0: [],
  charts1: []
};


/* ... */

charts['charts' + d].push( // ...

But if you are going to do this, you could simply use an array, where the indices are implicit:

var charts = [[],[]];

/* ... */

charts[d].push( // ...

edited Nov 22, 2015 at 12:47

answered Nov 22, 2015 at 12:19

Ben Aston

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3 Comments

Oriol Over a year ago

What's the point in using ES6 computed property names for this? Just use the number without brackets, or maybe an array initialiser.

Ben Aston Over a year ago

Number without the brackets is invalid syntax?

Oriol Over a year ago

See Object Initialiser. A PropertyName can be a NumericLiteral.

Andrey Stukalin · Accepted Answer · 2015-11-22 12:19:28Z

1

Create a new object with your arrays like

var ch = {
    charts0: [],
    charts1: [],
    charts2: [],
    charts3: []
}

Then you'll be able to do ch["charts" + d][i] etc..

answered Nov 22, 2015 at 12:19

Andrey Stukalin

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Comments

Bas Slagter · Accepted Answer · 2015-11-22 12:21:48Z

0

The way you are doing it right now is not possible (without using eval, which you shouldn't). You can however add an extra 'layer' with your variables by using an object. Like so:

var myData = {
    charts0: [],
    charts1: []
    charts2: []
    charts3: []
};

var newdata = data.split("|");
var newdates = dates.split(",");

for (i = 0; i < newdates.length; i++) { 
    for (d = 0; d < newdata.length; d++) { 
           var dataparts = newdata[d].split(",");
           myData['charts' + d].push({x: newdates[i], y: dataparts[i+1]});
    }
}

answered Nov 22, 2015 at 12:21

Bas Slagter

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