Dynamic array (try 2)

SirEddy · Nov 3, 2005

I am a bit lost here and think I did something like this in the past. Say I have array that I want to call the record length as follows:

dataRecords = data_fish.length
or
dataRecords = data_dogs.length
where data_fish and data_dogs are the arrays

But I want to have a function to dynamicaly call the length for example but want to use variables like:

recordCatagory = fish
getLength(recordCatagory)

or

recordCatagory = dogs
getLength(recordCatagory)

function getLength(recordCatagory) {
arrayToCall= "data_" + recordCatagory
dataRecords = arrayToCall.length
}

Is it possible?

trollacious · Nov 3, 2005

Yes, it's possible, but if you use that technique a lot, it will be slower than the less complicated method you're familiar with already:

Code:

getLength('dogs');
getlength('fish');

function getLength(recordCatagory)
{
var arrayToCall = eval("data_" + recordCatagory);
return arrayToCall.length;
}

eval() is quite expensive in clock cycles, and generally not recommended.

Lee

theniteowl · Nov 4, 2005

SirEddy, do you NEED to build the array name in the function or can you pass it in complete?

If you have the array declared data_dogs and you pass data_dogs into the function you actually pass the reference of the array, not just text so it will work directly when you test it's length.

Here is an example:

Code:

<HTML>
<HEAD>
<TITLE>Dynamic Option List</TITLE>
<SCRIPT language="javascript">
var data_dogs = new Array('First','Second','Third','Fourth');
var data_fish = new Array('Uno','Dos','Tres');

function getLength(recordCatagory) {
    dataRecords = recordCatagory.length
}
</SCRIPT>
</HEAD>
<BODY>
<input type="button" name="dogs" value="Dogs" onclick="getLength(data_dogs)"><br>
<input type="button" name="fish" value="Fish" onclick="getLength(data_fish)"><br>
</BODY>
</HTML>

Paranoid? ME?? WHO WANTS TO KNOW????

adam0101 · Nov 4, 2005

You could also do this:

Code:

function getLength(recordCatagory) {
    dataRecords = window["data_" + recordCatagory].length;
}

Or

Code:

function getLength(recordCatagory) {
    return window["data_" + recordCatagory].length;
}

See faq216-3858 for more info.

Adam
http://adameslinger.blogspot.com/

trollacious · Nov 4, 2005

I just realized that "Catagory" is a misspelling. Just copied and pasted what was originally written.

I'd go with adam0101's solution. I thought of that after I shut down my computer last night, but forgot about it until I saw it above.

Lee

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Dynamic array (try 2)

SirEddy

Programmer

trollacious

Programmer

theniteowl

Programmer

adam0101

Programmer

trollacious

Programmer

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