Add an element to the array

Question

I have a data array like this,

tourGuide: [
    {"location": "london"},
    {"location": "paris"},
    {"location": "frankfurt"}
]

I want to rewrite the tourGuide so that it will contain the indices too. so it will become something like:

tourGuide: [
    {"location": "london", "index":0},
    {"location": "paris", "index":1},
    {"location": "frankfurt","index":2}
]

I tried this:

var x, l=0;
for(x in tourGuide){
    tourGuide["index"] = l;
    l++;
}

but that may not be right approach.

Why would you want to do this? If you decide to change the order of the elements how are you going to keep up with the index? If you want to get the object from the array you need to know the index anyway. — Charles Sprayberry
– Charles Sprayberry, Commented May 18, 2012 at 2:16

mpm · Accepted Answer · 2012-05-18 02:16:32Z

2

var x, l=0;

for(x in tourGuide){

tourGuide[x]["index"] = l;
l++;

}

answered May 18, 2012 at 2:16

mpm

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Comments

Michael Berkowski · Accepted Answer · 2012-05-18 02:17:12Z

1

I would suggest you forget about the location property and just make a simple array. Unless you intend to add more properties later, a regular array will supply the numeric index for you. Just do:

var output = array();
for (var i=0; i<tourGuide.length; i++) {
  // Just stick each of the locations onto a plain old array
  output.push(tourGuide[i].location;
}

console.log(output);

answered May 18, 2012 at 2:17

Michael Berkowski

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Comments

Derek 朕會功夫 · Accepted Answer · 2012-05-18 02:28:50Z

1

Try this:

for(var i=0;i<tourGuide.length;i++){
    tourGuide[i].index=i
}

//----or more simplified...----

var i=0;
for(;i<tourGuide.length;){
    tourGuide[i].index=i++
}

LIVE DEMO: http://jsfiddle.net/DerekL/qvdzR/

But actually, you don't really have to create an index, since they are in an array, they already have an index value.

edited May 18, 2012 at 2:28

answered May 18, 2012 at 2:16

Derek 朕會功夫

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