how to copy array to array

Question

var ce_info=[
{location:"inchannel",name:"Jae Jung",volume:"50",url:"img/jae.jpeg",group:1},
{location:"inchannel",name:"Houston",volume:"50",url:"img/houston.jpeg",group:1},
{location:"inchannel",name:"Jun kuriha..",volume:"50",url:"img/jun.jpeg",group:1},
{location:"inchannel",name:"Andrea Melle",volume:"50",url:"img/andrea.jpeg",group:0},
{location:"inchannel",name:"Tomoaki Ohi..",volume:"50",url:"img/ohira.jpeg",group:0},
{location:"inchannel",name:"Woosuk Cha..",volume:"50",url:"img/woosuk.jpeg",group:0},
{location:"inchannel",name:"Luca Rigaz..",volume:"50",url:"img/luca.jpeg",group:0},
{location:"inchannel",name:"SooIn Nam",volume:"50",url:"img/sooin.jpeg",group:0}
];
var inch_info=[{location:"ichat",name:"",volume:"50",url:""}];

for(i=0;i<ce_info.length;i++)
{   

    if(ce_info[i].location=="inchat")
    {       

        inch_info[inchat_count].name=ce_info[i].name;
        inch_info[inchat_count].url=ce_info[i].url;
        inchat_count++;

    }
}

I am trying to copy ce_info to inch_info. It seems like it does not work.It occurs an error when I try to copy ce_info to inch_info Any thought?

This code wont do anything because there is no location inchat in the ce_info — Rick Hoving
– Rick Hoving, Commented Mar 28, 2012 at 7:51

Rony SP · Accepted Answer · 2012-03-28 07:36:03Z

4

Copying a native JS Array is easy. Use the Array.slice() method which creates a copy of part/all of the array.

var foo = ['a','b','c','d','e'];
var bar = foo.slice();

now foo and bar are 5 member arrays of 'a','b','c','d','e'

answered Mar 28, 2012 at 7:36

Rony SP

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Comments

Fabian · Accepted Answer · 2012-03-28 07:29:45Z

2

inchat_count seems to be uninitialized.

var inch_info=[{location:"icha",name:"",volume:"50",url:""}];
var inchat_count = 0; // You forgot this line!!
for(i=0;i<ce_info.length;i++)
{   

    if(ce_info[i].location=="inchat")
    {       

        inch_info[inchat_count].name=ce_info[i].name;
        inch_info[inchat_count].url=ce_info[i].url;
        inchat_count++;

    }
}

answered Mar 28, 2012 at 7:29

Fabian

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4 Comments

Mithun Satheesh Over a year ago

wat about using variable i itself ? instead of using one more variable inchat_count

draford Over a year ago

it gives me thie error Uncaught TypeError: Cannot set property 'name' of undefined

Fabian Over a year ago

@mithunsatheesh I also thought of the 'i' variable, but there is a 'if'-statement, which means probably not all of entries 'ce_info' will be copied, so we need another count-variable.

Fabian Over a year ago

@dradford You're right, I overlooked that... You'll need to add inch_info[inchat_count] = {}; before setting name and url. But I think Rick Hoving said it better.

Rick Hoving · Accepted Answer · 2012-03-28 07:59:58Z

1

You still have a typeO in your code

var inch_info=[{location:"ichat",name:"",volume:"50",url:""}];

shouldnt location be inchat instead of ichat? Because that is what you check for in this line

if(ce_info[i].location=="inchat")

Furthermore in ce_info there is no location named inchat so the result of this piece of code will not be executed. But if there where an element in ce_info that has the location inchat this will be the code you need to add the location and name to the inch_info array.

Change your for loop in this:

for(var eElem in ce_info)
{   
    if(ce_info[eElem].location=="inchannel")
    {
        var temp = {};
        temp.name=ce_info[eElem].name;
        temp.url=ce_info[eElem].url;
        inch_info.push(temp);

    }
}

edited Mar 28, 2012 at 7:59

answered Mar 28, 2012 at 7:25

Rick Hoving

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2 Comments

draford Over a year ago

I just want to copy name and url into inch_info i do not need to copy a whole array into inch_info

Rick Hoving Over a year ago

Edited my answer, is this more like you need?

Zain Shaikh · Accepted Answer · 2012-03-28 07:47:05Z

0

using jQuery you can achieve it so easily:

See a working demo here

following jQuery code makes sure that you do not have a by reference object of ce_info.

jQuery code:

var inch_info= jQuery.extend(true, {}, ce_info);

alert("inch_info: before changing text: "+inch_info[0].location);

inch_info[0].location = "hello world"

alert("inch_info: after changing text: "+inch_info[0].location);
alert("ce_info: after changing text: "+ce_info[0].location);

answered Mar 28, 2012 at 7:47

Zain Shaikh

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