Question

Please consider an array such as :

arrayAll = [1,2,3,4,5,6,7,8,9]

Is there a package that enable to do partitioning to obtain :

arrayALLPartionned = [[1,2,3],[4,5,6],[7,8,9]]

I can see how to do this with a for loop but would appreciate a “pre-made” function if existing.

Answer 1

If using Underscore.js, you can implement this with groupBy() and values()

function partition(items, size) {
    var result = _.groupBy(items, function(item, i) {
        return Math.floor(i/size);
    });
    return _.values(result);
}

(This is less ugly in CoffeeScript.)

jsFiddle: http://jsfiddle.net/MW3BS/