1.Let‘s implement the reject() function...
例:
var odds = reject([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; }); => [1, 3, 5]
soluction:
function reject(array, iterator) {
return array.filter(function(x){return !iterator(x)})
}
2.The numberOfOccurrences function must return the number of occurrences of an element in an array.
例:
var arr = [0,1,2,2,3]; arr.numberOfOccurrences(0) === 1; arr.numberOfOccurrences(4) === 0; arr.numberOfOccurrences(2) === 2; arr.numberOfOccurrences("a") === 0;
soluction:
Array.prototype.numberOfOccurrences = function() { return this.filter( function(num){ return search === num } ).length; }
JavaScript算法题(二) && 数组filter使用
原文：http://www.cnblogs.com/showtime813/p/4466398.html