javascript: how to call var by it's name string?

Question

I have

var mean = 20;
var median = 30;

I have function that should get parameter of type string ('mean' / 'median'), and do something with the parallel var:

function compute(varNameAsString){
  return varNameAsString.toVariable() + 5;
}

how can I implement the toVariable? I tried

varNameAsString.valueOf()

but it didn't work...

thanks!

possible duplicate http://stackoverflow.com/q/724857/526704 – DLeh Mar 06 '15 at 14:24 — DLeh, Mar 06 '15 at 14:24

score 1 · Answer 1 · edited May 23 '17 at 12:20

1

Use a hash table. Try this.

var values = { mean: 20, median: 30 };

function compute(varManeAsString){
  return values[varNameAsString] + 5;
}

That should work.

Of course, you could always use eval, but as the post I linked to says, the hash table is usually better.

edited May 23 '17 at 12:20

Community

answered Mar 06 '15 at 14:30

Cob

No, the "hash table" would be the proper solution here. Can you make edit your code to reflect the OPs actual example? – Bergi Mar 06 '15 at 14:32
Sure. I'll fix that now. – Cob Mar 06 '15 at 14:33
@Bergi, Sorry about that mistake. Please tell me is you see anything else that I should fix for this answer. I am not actually a huge user of javascript. – Cob Mar 06 '15 at 14:41
Thanks, +1 for the update! – Bergi Mar 06 '15 at 14:44

score 0 · Answer 2 · answered Mar 06 '15 at 14:25

0

Try:

return eval(varNameAsString) + 5;

answered Mar 06 '15 at 14:25

David P

score 0 · Answer 3 · answered Mar 06 '15 at 14:28

0

You can do window[varNameAsString]:

var mean = 20;
var median = 30;

function compute(varNameAsString){
  return window[varNameAsString] + 5;
} 

compute('median'); // Will output 35

answered Mar 06 '15 at 14:28

putvande

…but only if those variables are global, which they shouldn't be. – Bergi Mar 06 '15 at 14:31

3 Answers3