simple array question

Question

I have a 2 dimension array :

var fondetcaption = [
        ["fond/fond1.jpg","« aaa"],    
        ["fond/fond2.jpg","« bbb"],
        ["fond/fond3.jpg","« ccc"],
        ["fond/fond4.jpg","« ddd"]          
    ];

That array can have 4, 7, 10, any number of value in...

I like to know how many pair of value I have (it should return 4 in this case)

var howmany = fondetcaption.lenght; // doesn't work !

And after that... i will show fondetcaption[0][0] (the first background) and after that on click on a button i like to show the next : [1][0] and then next [2][0] and then [3][0] and then [0][0] again.... push doesn't seem to work.

Any idea?

Where do you use the array? because it works for me i.imgur.com/QIiGy.png .Your array is defined in a local scope so that might be your problem. — mhitza
– mhitza, Commented Jan 26, 2011 at 22:07

FatherStorm · Accepted Answer · 2011-01-26 22:04:36Z

5

check your spelling..

fondetcaption.length

answered Jan 26, 2011 at 22:04

FatherStorm

7,1711 gold badge24 silver badges27 bronze badges

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

Comments

T.J. Crowder · Accepted Answer · 2011-01-26 22:16:17Z

As the others have said, it's length, not lenght.

But no one seems to have addressed the second part of your question, so:

You don't need push to cycle through the values. All you need is an index:

var fondetcaption = [
    ["fond/fond1.jpg","« aaa"],    
    ["fond/fond2.jpg","« bbb"],
    ["fond/fond3.jpg","« ccc"],
    ["fond/fond4.jpg","« ddd"]          
];
var fondetcaptionIndex = 0;

// Call this when you click your button or whatever
function getNextBackground() {
    if (fondetcaptionIndex >= fondetcaption.length) {
        fondetcaptionIndex = 0;
    }
    return fondetcaption[fondetcaptionIndex++];
}

Or, if you like, you can just put the index directly on the array object, since JavaScript array objects can have arbitrary non-element properties and that helps keep the symbols together:

var fondetcaption = [
    ["fond/fond1.jpg","« aaa"],    
    ["fond/fond2.jpg","« bbb"],
    ["fond/fond3.jpg","« ccc"],
    ["fond/fond4.jpg","« ddd"]          
];
fondetcaption.index = 0;

// Call this when you click your button or whatever
function getNextBackground() {
    if (fondetcaption.index >= fondetcaption.length) {
        fondetcaption.index = 0;
    }
    return fondetcaption[fondetcaption.index++];
}

In fact, you can even make the function part of the array:

var fondetcaption = [
    ["fond/fond1.jpg","« aaa"],    
    ["fond/fond2.jpg","« bbb"],
    ["fond/fond3.jpg","« ccc"],
    ["fond/fond4.jpg","« ddd"]          
];
fondetcaption.index = 0;
fondetcaption.getNext = function() {
    if (this.index >= this.length) {
        this.index = 0;
    }
    return this[this.index++];
};

// Use
background = fondetcaption.getNext();

If making the array itself the container of those extra properties bothers you (it bothers some people), wrap the whole thing up in an object:

var fondetcaption = (function() {
    var index = 0,
        values = [
            ["fond/fond1.jpg","« aaa"],    
            ["fond/fond2.jpg","« bbb"],
            ["fond/fond3.jpg","« ccc"],
            ["fond/fond4.jpg","« ddd"]          
        ];

    function fondetcaption_getNext() {
        if (index >= values.length) {
            index = 0;
        }
        return values[index++];
    }

    return {
        values:  values,
        getNext: fondetcaption_getNext
    };
})();

// Sample use:
background = fondetcaption.getNext();

// Original array still accessible if desired as fondetcaption.values

you read the whole question and answer right (base on other answer) no wonder you have 43.4k under the hood !.. thanks

Rion Williams · Accepted Answer · 2011-01-26 22:04:02Z

3

Did you try:

var howmany = fondetcaption.length;

Your original post has a spelling error, lenght needs to be length.

answered Jan 26, 2011 at 22:04

Rion Williams

76.9k38 gold badges206 silver badges335 bronze badges

Comments

Bertrand Marron · Accepted Answer · 2011-01-26 22:04:12Z

3

Try length.

alert(fondetcaption.length);

answered Jan 26, 2011 at 22:04

Bertrand Marron

22.3k8 gold badges63 silver badges95 bronze badges

Comments

Dutchie432 · Accepted Answer · 2011-01-26 22:03:59Z

1

Not sure what's wrong since it works fine here..

var fondetcaption = [
        ["fond/fond1.jpg","« aaa"],    
        ["fond/fond2.jpg","« bbb"],
        ["fond/fond3.jpg","« ccc"],
        ["fond/fond4.jpg","« ddd"]          
];

alert(fondetcaption.length);

http://jsfiddle.net/tLPwp/

Perhaps fondetcaption.lenght is actually copied from code, and thusly spelled incorrectly.

answered Jan 26, 2011 at 22:03

Dutchie432

29.3k20 gold badges94 silver badges110 bronze badges

Comments

Spliffster · Accepted Answer · 2011-01-26 22:04:26Z

1

This returns the array's length: fondetcaption.length

answered Jan 26, 2011 at 22:04

Spliffster

7,2592 gold badges27 silver badges21 bronze badges

Comments

Pero · Accepted Answer · 2011-01-26 22:15:58Z

0

You have a typo in code. It should be var howmany = fondetcaption.length, and not ... fondetcaption.lenght.

I suggest you use tools like Firebug's, Chrome's, or Safari's Console. It can be very helpful, especially with the problems like these. I copy-pasted your code, tried it, and it works like charm. With the mentioned typo fixed, of course.

Cheers.

answered Jan 26, 2011 at 22:15

Pero

1,45118 silver badges21 bronze badges

1 Comment

T.J. Crowder Over a year ago

Five previous people already gave this answer (well six, but you can't see the one who realized they were duplicating and deleted). Why add yet another one? The debugging comment is valid, but it's a comment, not an answer.

Collectives™ on Stack Overflow

simple array question

7 Answers 7

Comments

1 Comment

Comments

Comments

Comments

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

Comments

1 Comment

Comments

Comments

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related