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hello ,

I have a array that I want to sort , the sorted array will be in asc
form and array keys will be maintained . Can anybody help me ?


states_array['1'] = 'Canada';
states_array['2'] = 'Netherland';
states_array['5'] = 'Africa';
states_array['3'] = 'India';
states_array['4'] = 'USA';

and the result after sorting will be

states_array['5'] = 'Africa';
states_array['1'] = 'Canada';
states_array['3'] = 'India';
states_array['2'] = 'Netherland';
states_array['4'] = 'USA';

Thanks,
Rahul

Rahul wrote:
> I have a array that I want to sort , the sorted array will be in asc
> form

What is `asc form'?

> and array keys will be maintained

An ECMAScript Array has properties with numeric name as indexes, not keys.
An ECMAScript Object has properties with arbitrary name, not keys.

> . Can anybody help me ?
>
> states_array['1'] = 'Canada';

I told why it is not necessary to quote a numeric property name.

> states_array['2'] = 'Netherland';
> states_array['5'] = 'Africa';
> states_array['3'] = 'India';
> states_array['4'] = 'USA';
>
> and the result after sorting will be
>
> states_array['5'] = 'Africa';
> states_array['1'] = 'Canada';
> states_array['3'] = 'India';
> states_array['2'] = 'Netherland';
> states_array['4'] = 'USA';

That is semantically equivalent. No sorting necessary.

The point of sorting is that the key for a value, or the value for a key,
*changes* according to the sort order.


PointedEars

Rahul wrote:
> hello ,
>
> I have a array that I want to sort , the sorted array will be in asc
> form and array keys will be maintained . Can anybody help me ?
>
>
> states_array['1'] = 'Canada';
> states_array['2'] = 'Netherland';
> states_array['5'] = 'Africa';
> states_array['3'] = 'India';
> states_array['4'] = 'USA';
>
> and the result after sorting will be
>
> states_array['5'] = 'Africa';
> states_array['1'] = 'Canada';
> states_array['3'] = 'India';
> states_array['2'] = 'Netherland';
> states_array['4'] = 'USA';

You want to do sorting on object properties; are you sure you want to do
this?

Rahul wrote:

> hello ,
>
> I have a array that I want to sort , the sorted array will be in asc
> form and array keys will be maintained . Can anybody help me ?
>
>
> states_array['1'] = 'Canada';
> states_array['2'] = 'Netherland';
> states_array['5'] = 'Africa';
> states_array['3'] = 'India';
> states_array['4'] = 'USA';
>
> and the result after sorting will be
>
> states_array['5'] = 'Africa';
> states_array['1'] = 'Canada';
> states_array['3'] = 'India';
> states_array['2'] = 'Netherland';
> states_array['4'] = 'USA';
>
> Thanks,
> Rahul


You have to store the indexes explicitly, for example like that:

var states = [
{
index : 1,
region : "Canada"
},
{
index : 2,
region : "Netherlands"
},
{
index : 3,
region : "Africa"
},
{
index : 4,
region : "India"
},
{
index : 5,
region : "USA"
}
];

To sort this array by key, you could do something like this

/*
* returns a sort function
*/
var sortByKey = function (key) {
return function (a, b) {
if (a && typeof a === "object") {
if (b && typeof b === "object") {
return a[key] - b[key];
}
return 1;
}
return -1;
};
};

states.sort(sortByKey("index"));
states.sort(sortByKey("region"));

Conrad Lender wrote:
> 2) Do the sorting on the client side. Here's an example implementation:
>
> var sorted = states_array
> .map(function(name, id) { return {id: id, name: name}; })
> .sort(function(a, b) { return a.name > b.name ? 1 : -1 })
> .filter(function(ele) { return ele; });

It seems that filter isn't doing much here?

Conrad Lender wrote:
>>> var sorted = states_array
>>> .map(function(name, id) { return {id: id, name: name}; })
>>> .sort(function(a, b) { return a.name > b.name ? 1 : -1 })
>>> .filter(function(ele) { return ele; });
>> It seems that filter isn't doing much here?
>
> The OP had an array with an undefined 0th element; I used filter() to
> remove this element from the result. Looking at it again, it would
> probably be more efficient to filter it out before the sort().

Yes, filtering should be as soon as possible, but
console.dir(states_array) doesn't show 0-th element?

Conrad Lender wrote:
>>> remove this element from the result. Looking at it again, it would
>>> probably be more efficient to filter it out before the sort().
>> Yes, filtering should be as soon as possible, but
>> console.dir(states_array) doesn't show 0-th element?
>
> Try console.log(states_array).

Tnx.

On Jun 8, 5:54*pm, Thomas 'PointedEars' Lahn <PointedE...@web.de>
wrote:
> Rahul wrote:
> > I have a array that I want to sort , the sorted array will be in asc
> > form
>
> What is `asc form'?
>
> > and array keys will be maintained
>
> An ECMAScript Array has properties with numeric name as indexes, not keys..
> An ECMAScript Object has properties with arbitrary name, not keys.
>
> > . Can anybody help me ?
>
> > states_array['1'] = 'Canada';
>
> I told why it is not necessary to quote a numeric property name.
>
> > states_array['2'] = 'Netherland';
> > states_array['5'] = 'Africa';
> > states_array['3'] = 'India';
> > states_array['4'] = 'USA';
>
> > and the result after sorting will be
>
> > states_array['5'] = 'Africa';
> > states_array['1'] = 'Canada';
> > states_array['3'] = 'India';
> > states_array['2'] = 'Netherland';
> > states_array['4'] = 'USA';
>
> That is semantically equivalent. *No sorting necessary.
>
> The point of sorting is that the key for a value, or the value for a key,
> *changes* according to the sort order.
>
> PointedEars

Explanation seems to be pure rubbish.

On Jun 8, 7:18*pm, Conrad Lender <crlen...@yahoo.com> wrote:
> On 08/06/09 14:21, Rahul wrote:
>
> > I have a array that I want to sort , the sorted array will be in asc
> > form and array keys will be maintained . Can anybody help me ?
>
> See Thomas's post about the difference between objects and arrays.
>
> > states_array['5'] = 'Africa';
> > states_array['1'] = 'Canada';
> > states_array['3'] = 'India';
> > states_array['2'] = 'Netherland';
> > states_array['4'] = 'USA';
>
> Just a wild guess... this looks like data to be used in a <select>
> element, and your "array keys" are database record ids. If that's the
> case, you have two options:
>
> 1) Do the sorting on the server side, and use a different data
> structure; for example:
>
> * var states = [
> * * * {id: 5, name: "Africa"},
> * * * {id: 1, name: "Canada"},
> * * * ... etc
> * ];
>
> Adjust the code that populates the dropdown to work with the new structure.
>
> 2) Do the sorting on the client side. Here's an example implementation:
>
> var sorted = states_array
> * * * * * * .map(function(name, id) { return {id: id, name: name}; })
> * * * * * * .sort(function(a, b) { return a.name > b.name ? 1: -1 })
> * * * * * * .filter(function(ele) { return ele; });
>
> // testing:
> for (var i = 0, len = sorted.length; i < len; ++i) {
> * * console.log(sorted[i].id + ": " + sorted[i].name);}
>
> // * 5: Africa
> // * 1: Canada
> // * 3: India
> // * 2: Netherland
> // * 4: USA
>
> "map" and "filter" are JavaScript 1.5 features, and are not supported by
> older browsers. You can retrofit them using the code snippets from these
> pages:
> <https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Object...>
> <https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Object...>
>
> You can also use traditional loops to prepare the sorted array.
>
> * - Conrad

Thanks Conrad, I am going to use your logic .
One more point , how to convert array format such as

states_array['5'] = 'Africa';
states_array['1'] = 'Canada';

to the format given below . Do you want me to do this at run time?

var states = [
{id: 5, name: "Africa"},
{id: 1, name: "Canada"}
];

Rahul wrote on 09 jun 2009 in comp.lang.javascript:
> Thomas:
>> The point of sorting is that the key for a value, or the value for a
>> key, *changes* according to the sort order.
>
> Explanation seems to be pure rubbish.

That was to be forseen, as the OQ was pure rubish.

[Garbage in, garbage out, remember.]

states_array['2'] = '';

1 That is not a javascript array, because an array has a numeric index.

2 An array is sorted by it's index.

===================================

If you want another sort, while "maintaining the [numeric] index",
you infact have to maintain the original array,
so you better use another array, an secondary index array:


<script type='text/javascript'>

var theArr = [];
var indexArr = [];
var temp;

theArr[2] = 'Netherland';
theArr[5] = 'Africa';
theArr[3] = 'India';
theArr[4] = 'USA';

// fill indexArr
var y = 0;
for(var x = 0; x < theArr.length; x++) {
if (theArr[x] != undefined) {
indexArr[y++] = x;
};
};

// bubblesort indexArr
for(x = 0; x < indexArr.length; x++) {
for(y = 0; y < indexArr.length-1; y++) {
if (theArr[indexArr[y]] > theArr[indexArr[y+1]]) {
temp = indexArr[y+1];
indexArr[y+1] = indexArr[y];
indexArr[y] = temp;
};
};
};

// show
for(x = 0; x < indexArr.length; x++) {
document.write(x + ': index: ' + indexArr[x]);
document.write(' value: ' + theArr[indexArr[x]] + '<br>');
};

</script>

==========================

This should work too, but I get an upsifde down result:

var indexArr = indexArr.sort(sortFunct);

function sortFunct(b,a) {
return (theArr[a] > theArr[b]);
};

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)