Filling multidimensionnal array in JavaScript

I've a little problem in JavaScript.

I need to get an array width date as keys and events as values.

In 开发者_运维技巧PHP I would do something like this :

$var = new array();
Loop
$var[$date][] = $event;
End loop

Do you know what I mean ?

Thanks, Regards

In javascript, you can create a data structure like that this way:

var events = {
    '2009-09-09': [],
    '2010-10-10': [],
    '2011-11-11': []
};

The events = { ... } is an object literal in javascript. Objects in javscript act very much like hashes with properties as keys, so this is essentially going to act as a hash keyed on dates. Each date is initialized with an empty array.

And you can fill it up with events like this

events[date].push(event);

If you don't know the dates ahead of time, you can dynamically fill the hash. So, you'd start with just an empty hash:

var events = {};

Then you'd check for the date key every time you go to add an event, like this:

if (!(date in events)) events[date] = [];
events[date].push(event);

The date in events checks to see if the key exists, and the ! negates it. So if the date key does not exist, it initializes the date key with an empty array. Then it pushes the event for that date as normal.

In Javascript key-value mappings are handled by Objects. An empty object is just {}. You can do this sort of thing like (note that var is a reserved word in Javascript so I can't copy your example exactly):

var variable = {};
var date_list = [1,2,3];
var event_list = [4,5,6];
for (i in date_list){
    var key = date_list[i];
    var value = event_list[i];
    variable[key] = value;
}

// variable now contains: {1:4, 2:5, 3:6}

console.log(variable[1]);
// prints 4

EDIT: That's the basic syntax. If you want to have an array for each key, just do something like that but with arrays instead of numbers in event_list. For example:

my_dates = {'2011': [1,2,3], '2010': [6,7,8]}

To add an element to a list you can use the push javascript method of array objects...

events_by_date = {};
...
for (var i=0; i<events.length; i++) {
    if (!events_by_date[events[i].date]) {
        // This is the first event on this date
        // so create the list
        events_by_date[events[i].date] = [];
    }
    // Add the event to the list of events in that date
    events_by_date[events[i].date].push(events[i]);
}