I'm trying to obtain a list of all elements that are in a JavaScript array, but I've noticed that using array.toString does not always show all the contents of the array, even when some elements of the array have been initialized. Is there any way to print each element of an array in JavaScript, along with the corresponding coordinates for each element? I want to find a way to print a list of all coordinates that have been defined in the array, along with the corresponding values for each coordinate.

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var coordinates = [];
coordinates[[0, 0, 3, 5]] = "Hello World";

coordinates[[0, 0, 3]] = "Hello World1";

console.log(coordinates[[0, 0, 3]]);
console.log(coordinates[[0, 0, 3, 5]]);
console.log(coordinates.toString()); //this doesn't print anything at all, despite the fact that some elements in this array are defined

I'm trying to obtain a list of all elements that are in a JavaScript array, but I've noticed that using array.toString does not always show all the contents of the array, even when some elements of the array have been initialized. Is there any way to print each element of an array in JavaScript, along with the corresponding coordinates for each element? I want to find a way to print a list of all coordinates that have been defined in the array, along with the corresponding values for each coordinate.

http://jsfiddle.net/GwgDN/3/

var coordinates = [];
coordinates[[0, 0, 3, 5]] = "Hello World";

coordinates[[0, 0, 3]] = "Hello World1";

console.log(coordinates[[0, 0, 3]]);
console.log(coordinates[[0, 0, 3, 5]]);
console.log(coordinates.toString()); //this doesn't print anything at all, despite the fact that some elements in this array are defined

• javascript
• arrays

• Id advise you to use Firefox and download the Firebug addon. I used to have q's like this, till I got the addon. – Robert Mailloux Commented Mar 12, 2013 at 5:41
• Or use Google Chrome browser, has great developer tools. – Amy Commented Mar 12, 2013 at 5:47
• I didn't downvote, but maybe it's because the question would be easy to answer with a small amount of research and/or reading. Sometimes it's tempting to downvote legitimate questions when it seems like the OP was stuck on something for 3 minutes before asking the question. – jahroy Commented Mar 12, 2013 at 5:58
• 1 despite the fact that some elements in this array are defined Arrays only take in integer indexes: [][0] = 1, []["string"] = 1 won't work. – Derek 朕會功夫 Commented Mar 12, 2013 at 6:02
• In your example, [0, 0, 3, 5] will turn into 0,0,3,5, creating an Object: {"0,0,3,5": "Hello World"}. Since there is no item in your Array, coordinates,toString() will output "". – Derek 朕會功夫 Commented Mar 12, 2013 at 6:11

5 Answers 5

Actually when you use coordinates[[0, 0, 3]] then this means coordinates object with [0, 0, 3] as key. It will not push an element to array but append a property to the object. So use this line which loop through objects. See this for other ways to loop through object properties,

Object.keys(coordinates).forEach(function(key) {
    console.log(key, coordinates[key]);
});

http://jsfiddle.net/GwgDN/17/

Use type 'object' instead 'array' for coordinates

var coordinates = {};
coordinates[[0, 0, 3, 5]] = "Hello World";

coordinates[[0, 0, 3]] = "Hello World1";

console.log(coordinates[[0, 0, 3]]);
console.log(coordinates[[0, 0, 3, 5]]);
console.log(JSON.stringify(coordinates));

http://jsfiddle.net/5eeHy/

for (i=0;i<coordinates.length;i++)
{
document.write(coordinates[i] + "<br >");
}

use join function to get all elements of array.use following code

for (var i in coordinates)
{
    if( typeof coordinates[i] == 'string' ){
        console.log( coordinates[i] + "<br >");
    }
}

Look at coordinates in the debugger and you will see that you have set the properties [0,0,3,5] and [0,0,3] of the object coordinates. That is although coordinates is an array you are not using it as an array.