Adding to array in for loop doesn't store value properly?

Question

OK.. I really must be crazy. Why would these not print out 3-5 for "a"? I've tried two different methodologies to have the array store 3-5 below, and both of them seem.. obvious. There must be something in the underlying translation that I'm just not seeing.

<script>
    var articlesKey = [];
    for(var i = 3; i < 6; i++) {
        articlesKey.push(i);
        document.write('<br>i:'+i);
    }
    for (a in articlesKey)
        document.write("<br>a:"+a);


    articlesKey = [];
    var count = 0;
    for(var i = 3; i < 6; i++) {
        articlesKey[count] = i;
        document.write('<br>i:'+i);
        count++;
    }
    for (a in articlesKey)
        document.write("<br>a:"+a);
</script>

It prints out:

i:3
i:4
i:5
a:0
a:1
a:2
i:3
i:4
i:5
a:0
a:1
a:2

Niet the Dark Absol · Accepted Answer · 2012-04-08 21:55:16Z

3

for( a in articlesKey) iterates a through the KEYS of articlesKey (letting you then get the values as articlesKey[a]). There is nothing wrong here.

answered Apr 8, 2012 at 21:55

Niet the Dark Absol

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Comments

MarioDS · Accepted Answer · 2012-04-08 21:57:37Z

0

That's very simply because a represents the array index in the loop, not the value at the index. Fix:

document.write("<br>a:"+articlesKey[a]);

answered Apr 8, 2012 at 21:57

MarioDS

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