How can I access an array using an objects name value?

Question

What I am trying to do

I am trying to access several arrays by passing a parameter to a function that is basically controls a slideshow. The parameter I pass to the function is the nameof a <a href=#" name="rebounding" onclick="nextPlayer(this.name)"></a>. Here is one of the arrays I am trying to access. var reboundingImgs = ['tyson_chandler.png', 'dwight_howard.png', 'zach_randolph.png', 'omer_asik.png', 'nikola_vucevic.png', 'joakim_noah.png'];

The problem

When I pass the parameter to the function that changes the image and I use the [index]instead of getting the index in the array called reboundingImgs[]I get the letter in the string parameter. e.g. parameter + "Imgs"[index] would be "b" if index was 2 and the parameter I pass in is "rebounding". I need to access the arrays using the parameter I pass in to show the right image from the right array( I have several arrays containing images e.g. scoringImgs[], reboundingImgs[], assistsImgs[], etc)

Here is my code

function nextPlayer(typeStatStr) {
    var numImgs = 6;
    var img = document.getElementById("slideImage");
    var imageName = img.name.split("_"); 
    var index = imageName[1];
    if (index == numImgs -1) {
        return;
    } 
    else {
        index++;
    }
    img.src = "..\\nbaart\\" + typeStatStr + "Imgs"[index];
    img.name = "image_" + index;
}

function prevPlayer(typeStatStr) {
    var img = document.getElementById("slideImage");
    var imageName = img.name.split("_");
    var index = imageName[1];
    if (index == 0) {
        return;
    }
    else {
            index--;
    }
    img.src = "..\\nbaart\\" + typeStatStr + "Imgs"[index];
    img.name = "image_" + index;
}

They are global. I load them in the <head> I do it like this so the browser can pre load them into memory. — Lexus de Vinco
– Lexus de Vinco, Commented Mar 2, 2013 at 14:04

Daniel Imms · Accepted Answer · 2013-03-02 14:05:33Z

3

Make an object which has properties that you can access given the name of the arrays:

var imgs = {};

imgs.rebounding = ['tyson_chandler.png', 'dwight_howard.png', 
                   'zach_randolph.png', 'omer_asik.png', 
                   'nikola_vucevic.png', 'joakim_noah.png'];

alert(imgs["rebounding"][0]); // tyson_chandler.png

answered Mar 2, 2013 at 14:05

Daniel Imms

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3 Comments

Lexus de Vinco Over a year ago

Thanks for showing me this approach. It's more object-oriented right? Together with you and Juans answer my slideshow is working.

Daniel Imms Over a year ago

I don't think object-oriented is the right word, it's more maintainable as you will end up using less code.

Daniel Imms Over a year ago

Saves you writing specific stuff for each name. This method is much more object-oriented than Juan Mellado's however, attaching data to window that could easily be in its own variable is bad practice.

Juan Mellado · Accepted Answer · 2013-03-02 14:02:11Z

3

Why don't pass the proper array as a parameter to the function?

nextPlayer(reboundingImgs);

And then just:

typeStatStr[index];

Anyway, if the arrays are some sort of global variables (window scope?) then you can do this:

window[typeStatStr + "Imgs"][index];

answered Mar 2, 2013 at 14:02

Juan Mellado

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1 Comment

Lexus de Vinco Over a year ago

I didn't think about sending the proper array (i am pretty new to programming). After I did that I figured out that I had to make 2 new functions though. The new functions find out which of the arrays to send to nextPlayer() and prevPlayer() respectively. I also tested your second suggestion window[typeStatStr + "Imgs"[index]; and it worked good, but since it only works with global variables I decided to not use it.

Jason · Accepted Answer · 2013-03-02 14:02:05Z

2

String is just type character array so by doing: "Imgs"[index]; you are accessing the index-th element of the array of "Imgs". For instance "Imgs"[2] == 'g'.

If you want to access the index-th element of the array Imgs then you should do:

Imgs[index]; //Without the quotes

answered Mar 2, 2013 at 14:02

Jason

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2 Comments

Matt Browne Over a year ago

This is indeed the problem. @JuanMellado's answer shows you you can get the array variable instead of the string. Although making an imgs object as Tyriar suggests is nicer IMO.

Lexus de Vinco Over a year ago

Actually im trying to concatenate typeStatStr, which is a string, with another string "Imgs" so that it forms the name of an array and then access that array with [index].

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