使用数字键访问非数字密钥对象是有效的JavaScript吗？

Question

I have an object

data = {
    'choiceA' : 'Long-Wear',
    'choiceB' : 'Anti-Age Lifting/Firming',
    'choiceC' : 'Replenishing/ Moisturizing',
    'choiceD' : 'Natural/ True-to-Skin',
    'choiceE' : 'Smoothing/ Illuminating'
}    

and I need to retrieve the fourth value given an integer

 position = 3;

normally I would write

 key = $.inArray( position, ['choiceA', 'choiceB', 'choiceC', 'choiceD', 'choiceE']);
 answer = data[key];

but is it valid javascript to access the object directly with the numeric key like this?

 answer = data[position];  // where position is an integer

EDIT:
some bad code I wrote as I'm using $.inArray backwards!
I meant to write

 arr = ['choiceA', 'choiceB', 'choiceC', 'choiceD', 'choiceE'];
 key = arr[position];
 answer = data[key];

Answer 1

No, it is not valid until you have numeric object "keys", ie

data = {
    '1' : 'Long-Wear',
    '2' : 'Anti-Age Lifting/Firming',
    '3' : 'Replenishing/ Moisturizing',
    '4' : 'Natural/ True-to-Skin',
    '5' : 'Smoothing/ Illuminating'
};

Also, it is important to note, that properties in JavaScript objects are not sorted . So your solution is the best way to go as I see.

Answer 2

if you would have tried it, you would have seen that it is not valid. even more it is not working!

data[position]

would return undefined in your example...

Answer 3

Two things:

1. Javascript keys are always strings. If you pass something else (say, a number) it is converted to a string. (For example, try indexing a array with array["3"] and it should work

2. Javascript objects are not ordered! You cannot get back the i-th key value pair portably. Instead you should use an array to store things (or something like that):

    data = [ { name:'choiceA', value: 'Long-Wear'}, { name:'choiceB', value: 'Anti-Age Lifting/Firming'} ]; 

   One thing you could do if you can't change the data representation is iterate though your object using a for-in loop, plus a counting variable. However, this approach is not portable, since not all browsers iterate in the same order as the keys were defined.