Using JS to implement an array merging method (requires to go to the weight)

Recently found an interview problem, using JS to implement an array merge method (requires to go to the weight). We know that the Concat method merges two arrays and returns a new array, and the new array contains each element in the old array, which is [1,2,3,2,3,4] after [three-way] combined with [2,3,4]. So how to achieve, can combine and can go heavy?

The idea is to put the value of the target array as a key into an object, and in this process, the duplicate values are filtered out so that the duplicate values are excluded.

Two arrays, a = [three-to-one], B = [2,3,4], requires the merged array to be [1,2,3,4]

Array.prototype.unique = function () {var a = {};for (var i = 0; i < this.length; i++) {if (typeof a[this[i]] = = "undefined" ) A[this[i]] = 1;} This.length = 0;for (var i in a) this[this.length] = I;return this;} var a = [1,2,3];var B = [2,3,4];var c = A.concat (b). unique ();

Two arrays, a = [three-to-one], B = [2,3,4], requires the merged array to be [1,4]

Array.prototype.unique2 = function () {var a = {},b = {},n = This.length;for (var i = 0; i < n; i++) {if (typeof (B[this[i)]) ! = "undefined") continue;if (typeof (A[this[i]]) = = "undefined") {A[this[i]] = 1;} Else{b[this[i]] = 1;delete a[this[i];}} This.length = 0;for (var i in a) this[this.length] = I;return this;} var a = [1,2,3,4];var b = [2,3,5,7];var d = a.concat (b). Unique2 ();

Reference Link: http://www.jb51.net/article/21916.htm

http://bbs.csdn.net/topics/190040118

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Using JS to implement an array merging method (requires to go to the weight)