CODEWITHSUNDEEP
javascriptstringconcatenation
Mickey
Mickey

Reputation: 2405

javascript - how to combine a static value and a dynamic value to get the value of an existing string

var a_0, a_1, a_2 = 0;

function onclick( id ) { 
   // id is either 0,1 or 2

   // echos 'a_0', 'a_1' or 'a_2', but I need it to echo "0".
   alert( 'a_' + id ); 
}

What am I doing wrong?

Upvotes: 1

Views: 2198

Answers (4)

david
david

Reputation: 18288

instead of naming your vars a_0, a_1 etc, use an array

var a=[];
a[0]=a[1]=a[2]=0;

function onclick(id){
  alert(a[id]);
}

Upvotes: 2

sdleihssirhc
sdleihssirhc

Reputation: 42496

Instead of declaring a_0, a_1, and a_2 as global variables, put them in an object:

var a_x = {
    a_0: 0,
    a_1: 0,
    a_2: 0
}

Then you can access those properties like this: a_x["a_" + id].

Upvotes: 4

roufamatic
roufamatic

Reputation: 18495

If you trust the event source, you could do this:

alert(eval('a_'+id))

Upvotes: 0

GreenWebDev
GreenWebDev

Reputation: 548

You need to use eval()

alert(eval('a_'+id));

eval() isn't usually recommended, though, but it depends on what you're trying to achieve.

Upvotes: 1

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