Javascript/jquery: get value from a combined key value array

Question

I am so ashamed of asking such a basic thing but I have been trying to work it out for a long time now and I cannot figure it out :(

I have two arrays. One contains keys and the other values.

I have combined them so I can have one array with the key value pair:

var combinedArray = [];
var keysArray = [];
var valuesArray = [];
keysArray = ["LND", "NY", "MAD"];
valuesArray = ["London", "New York", "Madrid"];
var keysArrayLength = keysArray.length;

for (var i = 0; i < keysArrayLength; i++) 
{  
 combinedArray.push({
 key: keysArray[i],
 value: valuesArray[i]
 });  
}

Now I need to get the value of a certain key.

For example, I want to have in a variable the value of key "LND"

So I do:

var result = $.grep(combinedArray, function(e){ return e.key == 'LND'; });

But in result, I get a [Object, Object] instead of London

What am I doing wrong?

Thanks!

Regent · Accepted Answer · 2014-09-17 10:18:46Z

1

$.grep will return to you an array, which consists of objects (which has key and value fields). So to get value you can use:

var result = $.grep(combinedArray, function(e){ return e.key == 'LND'; });
alert(result[0].value);

Fiddle.

answered Sep 17, 2014 at 10:18

Regent

5,1743 gold badges23 silver badges36 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Spokey · Accepted Answer · 2014-09-17 10:20:18Z

From the documentation

The $.grep() method removes items from an array as necessary so that all remaining items pass a provided test

meaning that the result is an array containing the object that matches your filter (is this case the key)

So you'll get it as you normally do from an array result[0].value

var combinedArray = [];
var keysArray = [];
var valuesArray = [];
keysArray = ["LND", "NY", "MAD"];
valuesArray = ["London", "New York", "Madrid"];
var keysArrayLength = keysArray.length;

for (var i = 0; i < keysArrayLength; i++){  
   combinedArray.push({
      key: keysArray[i],
      value: valuesArray[i]
   });  
}

var result = $.grep(combinedArray, function(e){ return e.key === 'LND'; });

document.write(result[0].value);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

Kiran Shinde · Accepted Answer · 2014-09-17 10:28:14Z

0

.grep creates array you must use this kind of code

var combinedArray = [];
var keysArray = [];
var valuesArray = [];
keysArray = ["LND", "NY", "MAD"];
valuesArray = ["London", "New York", "Madrid"];
var keysArrayLength = keysArray.length;

for (var i = 0; i < keysArrayLength; i++) 
{  
 combinedArray.push({
 key: keysArray[i],
 value: valuesArray[i]
 });  
}

var result = $.grep(combinedArray, function(e){ return e.key == 'LND'; });

console.log(combinedArray);
alert(result[0].value);

Example http://jsfiddle.net/6hza5m5e/1/

answered Sep 17, 2014 at 10:28

Kiran Shinde

6,0326 gold badges30 silver badges45 bronze badges

Collectives™ on Stack Overflow

Javascript/jquery: get value from a combined key value array

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related