Create new Javascript array with field names

Question

I have a data file that I'm reading into an array. The array created by the original data file looks like this:

var originalArray = [ {vendor: 2001, bananas: 50, apples:75, oranges: 12},
                      {vendor: 2002, bananas: 25, apples:60, oranges: 82},
                      {vendor: 2003, bananas: 36, apples:41, oranges: 73},
                      {vendor: 2004, bananas: 59, apples:62, oranges: 87}];

I select a vendor from the array using .filter (this is working fine) but then I need to change the new array (the one that contains only one vendor code) into an array that looks like this.

var desiredArray = [ {fruitName: "bananas", qty: 50},
                     {fruitName: "apples", qty: 75 },
                     {fruitName: "oranges", qty: 12} ];

Using .push I can get the quantities, but how can I get the fruit names to go from field names to values in the "fruitName" field?

Show the code you are using with .push, it is probably a simple fix. — Matt Dodge
– Matt Dodge, Commented Mar 25, 2013 at 16:24
I'm filling the result array using .push as follows. However, it doesn't give me the field names and the result array contains only one element with three values, rather than three elements with one value each. var desiredVendor = originalArray.filter(matchVendor); var result = []; for(var i = 0; i < desiredVendor.length; i++){ result.push(desiredVendor[i].bananas); result.push(desiredVendor[i].apples); result.push(desiredVendor[i].oranges); } — DG_Montana
– DG_Montana, Commented Mar 25, 2013 at 16:33
See my answer below, based on your comment here you'd set selectedVendor like this var selectedVendor = desiredVendor[0]; and then use the in loop like the example instead of using the index based for loop you're using now. — clav
– clav, Commented Mar 25, 2013 at 16:47

clav · Accepted Answer · 2013-03-25 16:31:13Z

6

If you've got the selected vendor object, you can do something like this to create the desiredArray.

var desiredArray = [];
var selectedVendor = originalArray[2]; // this is the vendor you got via .filter

for(property in selectedVendor) {
    if(property !== 'vendor') {
        desiredArray.push({fruitName: property, qty: selectedVendor[property]});
    }
}

answered Mar 25, 2013 at 16:31

clav

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1 Comment

DG_Montana Over a year ago

Thanks - this did the trick with just one small edit. I had to access the [0] element of originalArray rather than the [2] element. Thanks for the quick response!

Alberto De Caro · Accepted Answer · 2013-03-25 16:38:02Z

1

Use the for...in loop:

    var currentVendor;
    var desiredArray = [];

    //ok, this is only an example
    currentVendor = {vendor: 2001, bananas: 50, apples:75, oranges: 12};
    for (var prop in currentVendor) {
        if(prop!='vendor')
            desiredArray.push({fruitName: prop, qty: currentVendor[prop]});
    }

answered Mar 25, 2013 at 16:38

Alberto De Caro

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Comments

karthick · Accepted Answer · 2013-03-25 17:07:26Z

1

   var a = [{vendor:2001,apple :50,orange:20},{vendor:2002,apple:50, orange:10}];

   var matchedVendor = 2001;

For Filter

    var filteredArray = [];
    for (var i=0; i < a.length; i++){
    if(a[i].vendor === matchedVendor){
     filteredArray = a[i];
          break;
     }}


    var desiredArray = [];

    for(prop in filteredArray){
    if(prop !== "vendor"){
        desiredArray.push({fruitName:prop,qty:filteredArray[prop]});
    }
 }

answered Mar 25, 2013 at 17:07

karthick

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Comments

rab · Accepted Answer · 2013-03-25 17:12:46Z

1

Try this

var vendorId = 2001;

var desiredArray = originalArray.filter( function( v ) {

    return v.vendor == vendorId ;

}).map( function( v ){

    var s = [];

    for ( var i in v ){

        if ( i == 'vendor' ) continue;

        s.push( {fruitName: i , qty: v[i] } );            
    }
    return s;

}).pop();

The desiredArray has value

[ {fruitName: "bananas", qty: 50},
  {fruitName: "apples", qty: 75 },
  {fruitName: "oranges", qty: 12} ]

edited Mar 25, 2013 at 17:12

answered Mar 25, 2013 at 16:34

rab

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Comments

Stuart M · Accepted Answer · 2013-03-25 16:35:21Z

0

var fruit = {};
for (var i = 0; i < originalArray.length; i++) {
  for (var key in originalArray[i]) {
    if (key != selectedVendor)
      continue;
    if (!fruit[key])
      fruit[key] = 0;
    fruit[key] += originalArray[i][key];
  }
}
var desiredArray = [];
for (var fruitName in fruit) {
  desiredArray.push({fruit: fruitName, qty: fruit[fruitName]});
}

answered Mar 25, 2013 at 16:35

Stuart M

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