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I was wondering if there's a way to get the length of a second-level array, for example :

var arr = new Array();
arr[0] = new Array();

arr[0][0] = 'a';
arr[0][1] = 'a';
arr[0][2] = 'a';

I tried this, but without success :

arr[0].length;

Cheers!

EDIT

The evil code is as follows.

This is the function that I use to fill the array, wich works as expected :

function input_text(action, id) {
    if (action == 'add') {
        var i = info.length;
        if (i != 0) i++;
        info[i] = new Array();
        info[i]['type'] = 'input';
        info[i]['subtype'] = 'text';
        info[i]['nome'] = $('#input_text_form input[name="input_text_nome"]').val();
        info[i]['name'] = $('#input_text_form input[name="input_text_name"]').val();
        info[i]['id'] = $('#input_text_form input[name="input_text_id"]').val();
        info[i]['maxlenght'] = $('#input_text_form input[name="input_maxlenght"]').val();
        info[i]['default'] = $('#input_text_form input[name="input_text_default"]').val();
        info[i]['js'] = $('#input_text_form input[name="input_text_js"]').val();
    }
}

.. and this is a function to build a JSON string from the array. You may notice that I count the sublevel arrays length several times, in order to prevent the string from ending wrong, like ,}

function toJSON () {
    var fll = info.length;
    var sll = 0;
    var tll = 0;
    var i;
    var x;
    var z;
    var w;
    var b;
    json = '{';
    for (i in info) {
        json += '"'+i+'":{';
        sll = info[i].length;
        alert(sll);
        z = 0;
        for (x in info[i]) {
            if ($.isArray(info[i][x]))  {
                json += '"'+x+'":{';
                tll = info[i][x].length;
                w = 0;
                for (b in info[i][x]) {
                    tll == w ? json += '"'+b+'" : "'+info[i][x][b]+'"' : json += '"'+b+'" : "'+info[i][x][b]+'",';
                    w++;
                }
                sll == z ? json += '}' : json += '},';
            } else {
                sll == z ? json += '"'+x+'" : "'+info[i][x]+'"' : json += '"'+x+'" : "'+info[i][x]+'",';
            }
            z++;
        }
        fll == i ? json += '}' : json += '},';
    }

    json += '}';
}

Everytime I print the value of any of the fll, sll and tll variables, it gives me zero.

I was wondering if there's a way to get the length of a second-level array, for example :

var arr = new Array();
arr[0] = new Array();

arr[0][0] = 'a';
arr[0][1] = 'a';
arr[0][2] = 'a';

I tried this, but without success :

arr[0].length;

Cheers!

EDIT

The evil code is as follows.

This is the function that I use to fill the array, wich works as expected :

function input_text(action, id) {
    if (action == 'add') {
        var i = info.length;
        if (i != 0) i++;
        info[i] = new Array();
        info[i]['type'] = 'input';
        info[i]['subtype'] = 'text';
        info[i]['nome'] = $('#input_text_form input[name="input_text_nome"]').val();
        info[i]['name'] = $('#input_text_form input[name="input_text_name"]').val();
        info[i]['id'] = $('#input_text_form input[name="input_text_id"]').val();
        info[i]['maxlenght'] = $('#input_text_form input[name="input_maxlenght"]').val();
        info[i]['default'] = $('#input_text_form input[name="input_text_default"]').val();
        info[i]['js'] = $('#input_text_form input[name="input_text_js"]').val();
    }
}

.. and this is a function to build a JSON string from the array. You may notice that I count the sublevel arrays length several times, in order to prevent the string from ending wrong, like ,}

function toJSON () {
    var fll = info.length;
    var sll = 0;
    var tll = 0;
    var i;
    var x;
    var z;
    var w;
    var b;
    json = '{';
    for (i in info) {
        json += '"'+i+'":{';
        sll = info[i].length;
        alert(sll);
        z = 0;
        for (x in info[i]) {
            if ($.isArray(info[i][x]))  {
                json += '"'+x+'":{';
                tll = info[i][x].length;
                w = 0;
                for (b in info[i][x]) {
                    tll == w ? json += '"'+b+'" : "'+info[i][x][b]+'"' : json += '"'+b+'" : "'+info[i][x][b]+'",';
                    w++;
                }
                sll == z ? json += '}' : json += '},';
            } else {
                sll == z ? json += '"'+x+'" : "'+info[i][x]+'"' : json += '"'+x+'" : "'+info[i][x]+'",';
            }
            z++;
        }
        fll == i ? json += '}' : json += '},';
    }

    json += '}';
}

Everytime I print the value of any of the fll, sll and tll variables, it gives me zero.

• javascript
• arrays

Share Improve this question Follow edited Aug 2, 2010 at 18:24 yoda asked Aug 2, 2010 at 18:13 yodayoda 11k1919 gold badges6767 silver badges9393 bronze badges 6

• thanks, still, I've tryed with "both words" without success. – yoda Commented Aug 2, 2010 at 18:15
• 1 * Looks at title * Well, at least he's consistent. More than I can say for many programmers. – Kenan Banks Commented Aug 2, 2010 at 18:16
• 1 You should instantiate your arrays using [] instead of new Array(). Mostly the same, but [] is much shorter and the Array function can be messed with. – Cristian Sanchez Commented Aug 2, 2010 at 18:26
• Thanks @Daniel, but in this case apparently changed nothing, so I suppose it wasn't messing arround. Still, I'll start using that method :) – yoda Commented Aug 2, 2010 at 18:29
• 1 Just wondering: why don't you use JSON.stringify from json2.js? – Marcel Korpel Commented Aug 2, 2010 at 19:18

 |  Show 1 more ment

3 Answers 3

Sorted by: Reset to default 5

You are essentially creating an object with the string indexes. You can only get the length if it is a true array.

arr[0] = [];
arr[0][0] = 134;
arr[0][1] = 264;

arr[0].length; // will work

arr[1] = {};
arr[1]['str1'] = 134;
arr[1]['str2'] = 256;

arr[1].length; // will not work

See this question for more info: Length of a JavaScript object

Did you mispell it? Try:

arr[0].length;

It works for me:

var arr = new Array();
arr[0] = new Array();

arr[0][0] = 'a';
arr[0][1] = 'a';
arr[0][2] = 'a';

console.log(arr[0].length);

Result:

3

Check for yourself here.

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