CODEWITHSUNDEEP
javascriptarrays
Trombone0904
Trombone0904

Reputation: 4258

add values to multidemensional array

I have this javascript code which generate a multi array with static values:

var items = [ ["red", "blue"], ["green", "yellow"] ];
console.log(items[1][1]); // green

but now I would like to fill the values dynamically. I tried this:

var items = [[]];
$.each($("input[name='checkboxColors1']:checked"), function(){            
   items[0].push($(this).val());
});

$.each($("input[name='checkboxColors2']:checked"), function(){            
    items[1].push($(this).val());
});

items[0].push... works, but items[1] not

TypeError: items[1] is undefined

Where is my fault?

Upvotes: 0

Views: 76

Answers (6)

Eyal c
Eyal c

Reputation: 1663

Be careful when you combine static multi-dimension array, with dynamically adding elements with push.

Try the following code, that is dynamic for the two dimensions.

var checkBoxGroupNames = ['checkboxColors1', 'checkboxColors2'];
var items = [];

var checkedChkBoxes = [];

for (var i = 0; i < checkBoxGroupNames.length; i++) {
    checkedChkBoxes = [];

    $.each($("input[name=" + checkBoxGroupNames[i] + "]:checked"), function(){
        checkedChkBoxes.push($(this).val());
    });

    items.push(checkedChkBoxes);
}

console.log(items); // items now holds the two dimension array

For a cleaner code, you may put the logic that find checked checkboxes per group - in a function.

var checkBoxGroupNames = ['checkboxColors1', 'checkboxColors2'];
var items = [];

$.each(checkBoxGroupNames, function(){
  items.push(GetCheckedChkBoxes(this));
});

console.log(items); // items now holds the two dimension array

function GetCheckedChkBoxes(chkBoxGroupName) {
  checkedChkBoxes = [];

  $.each($("input[name=" + chkBoxGroupName + "]:checked"), function(){
    checkedChkBoxes.push($(this).val());
  });

  return checkedChkBoxes;
}

Upvotes: 0

SINGH
SINGH

Reputation: 397

The best way to do it by creating a Array object and assign values dynamically. In this way you can also define string key as well.Please see below

var items = new Array();

    items[0] = 1;
    items[1] = 2;
    console.log(items);

//Uncomment above block to test.
var items = new Array();
var items0 = [];
var items1 = [];
$.each($("input[name='checkboxColors1']:checked"), function(){            
   items0 = $(this).val();
});

$.each($("input[name='checkboxColors2']:checked"), function(){            
    items1 = $(this).val();
});
items[0] = items0;
items[1] = items1;

Upvotes: 0

Leandro Castro
Leandro Castro

Reputation: 251

I think you are confused about "push" function. This function insert a new element on the last position of array.

For example

var items = ["grape"];
items.push("apple"); 
console.log(items); //["grape", "apple"].

Upvotes: 0

Yanick Frehner
Yanick Frehner

Reputation: 21

You cannot push into an undefined array, you first need to create the array.

You're code has to look like this:

var items = [[], []];
$.each($("input[name='checkboxColors1']:checked"), function(){            
   items[0].push($(this).val());
});

$.each($("input[name='checkboxColors2']:checked"), function(){            
    items[1].push($(this).val());
});

Then it should work properly.

Upvotes: 1

MarcoS
MarcoS

Reputation: 17711

Javascript is asynchronous... You can't expect two functions to be executed sequentially... :-)

This way can work... But you must initialize your initial array this way:

var items = [ [], [] ];

Since with

var items = [[]];

You only define one internal array inside the external array (items[0]), but you want two (items[0], items[1]).

Upvotes: 2

Suxino
Suxino

Reputation: 169

var items = [[]]; You issue is here.

items[0] is an array. but items[1] is undefined. In order to work you need to define items as [[],[]]

Or to make it more dynamic you could do check before that $.each if the items[1] exists and if not create it

Upvotes: 2

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