JS数组方法扩展

/****************************************************

*CreateBy:joe zhou

*CreateDate:2011-9-20

*Description:数组统计函数

****************************************************/

$.extend({

    max: function (arr) {

        return cacl(arr, function (item, max) {

            if (!(max > item)) {

                return item;

            }

            else {

                return max;

            }

        });

    },

    min: function (arr) {

        return cacl(arr, function (item, min) {

            if (!(min < item)) {

                return item;

            }

            else {

                return min;

            }

        });

    },

    sum: function (arr) {

        return cacl(arr, function (item, sum) {

            if (typeof (sum) == 'undefined') {

                return item;

            }

            else {

                return sum += item;

            }

        });

    },

    avg: function (arr) {

        if (typeof (arr) == 'undefined' || arr.length == 0) {

            return 0;

        }

        return this.sum(arr) / arr.length;

    }

});



$.fn.extend({

    max: function () {

        return $.max(this.get());

    },

    min: function () {

        return $.min(this.get());

    },

    sum: function () {

        return $.sum(this.get());

    },

    avg: function () {

        return $.avg(this.get());

    }

});



function cacl(arr, callback) {

    var ret;

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

        ret = callback(arr[i], ret);

    }

    return ret;

}



Array.prototype.max = function () {

    return cacl(this, function (item, max) {

        if (!(max > item)) {

            return item;

        }

        else {

            return max;

        }

    });

};

Array.prototype.min = function () {

    return cacl(this, function (item, min) {

        if (!(min < item)) {

            return item;

        }

        else {

            return min;

        }

    });

};

Array.prototype.sum = function () {

    return cacl(this, function (item, sum) {

        if (typeof (sum) == 'undefined') {

            return item;

        }

        else {

            return sum += item;

        }

    });

};

Array.prototype.avg = function () {

    if (this.length == 0) {

        return 0;

    }

    return this.sum(this) / this.length;

};