how to get the value 'dynamically' from an associative array in javascript?

Question

i am trying to get a value from a key stored on a string variable proyNombre, but whenever i call it via the common method "myAssociativeArray.MyKey", it gets the variable 'proyNombre' as the key, instead of getting its value and passing it as a key.

proyectos.each(function(index){
    var proyNombre = this.value;

    if(!(proyNombre in myArray)){ // whenever the variable is undefined, define it
        myArray[proyNombre] = horas[index].value-0 + minutos[index].value/60;
    }
    else{
        console.log(myArray.proyNombre); //This doesnt work, it tries to give me the value for the key 'proyNombre' instead of looking for the proyNombre variable
        console.log(myArray.this.value); //doesnt work either
    }

});

Note that JavaScript doesn't have associative arrays - just objects. — alex
– alex, Commented Dec 3, 2010 at 1:58

sje397 · Accepted Answer · 2010-12-03 02:16:17Z

2

Try:

console.log(myArray[proyNombre]);

myArray is actually an object in javascript. You can access object properties with object.propertyName or, object['propertyName']. If your variable proyNombre contained the name of a property (which it does) you can use the second form, like I did above. object.proyNombre is invalid - proyNombre is a variable. You can't do for example:

var myObject = {};
myObject.test = 'test string';

var s = 'test';
console.log(myObject.s); // wrong!!

but you could then do:

console.log(myObject.test);
console.log(myObject['test']);
console.log(myObject[s]);

edited Dec 3, 2010 at 2:16

answered Dec 3, 2010 at 1:58

sje397

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1 Comment

Char Over a year ago

whenever the 8 minutes for best answer timer lets me

Dark Falcon · Accepted Answer · 2010-12-03 01:59:31Z

2

You need to use the same syntax you used to set the value:

console.log(myArray[proyNombre]);

answered Dec 3, 2010 at 1:59

Dark Falcon

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2 Comments

Char Over a year ago

seems like you have copied your answe from sje397

Dark Falcon Over a year ago

Nope, just the simplest of Javascript programming questions :)

Jakub Hampl · Accepted Answer · 2010-12-03 01:58:33Z

1

Simply access the value with myArray[proyNombre].

answered Dec 3, 2010 at 1:58

Jakub Hampl

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1 Comment

Char Over a year ago

thank you both, i gave the best answer to the fist one replying, both your solutions works. thanks a lot.

01001111 · Accepted Answer · 2010-12-03 02:04:19Z

1

You're doing it right in the assignment: myArray[proyNombre]. You can use the same method to retrieve the variable.

If you change:

console.log(myArray.proyNombre);
console.log(myArray.this.value);

to

console.log(myArray[proyNombre]);
console.log(myArray[this.value]);

You should get the same value (the value for the key represented by the variable proyNombre) logged twice.

It's true that Javascript doesn't have associative arrays but objects in Javascript can be treated like associative arrays when accessing their members.

answered Dec 3, 2010 at 2:04

01001111

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