js takes the intersection of two arrays | difference set | union set | complement set | deduplication example code_javascript skills

复制代码 代码如下:

/**
* each is a set iteration function that accepts a function as a parameter and a set of optional parameters
* This iteration function sequentially calculates each element of the set and the optional parameters using the function, and calculates The result set returned is
{%example
<script> <br>var a = [1,2,3,4].each(function(x){return x > 2 ? x : null }); <br>var b = [1,2,3,4].each(function(x){return x < 0 ? x : null}); <BR>alert(a); <BR>alert (b); <BR></script>
%}
* @param {Function} fn Function for iterative determination
* @param more ... Zero or more optional User-defined parameters
* @returns {Array} result set, if there is no result, return an empty set
*/
Array.prototype.each = function(fn){
fn = fn || Function.K;
var a = [];
var args = Array.prototype.slice.call(arguments, 1);
for(var i = 0; i < this.length; i ){
var res = fn.apply(this,[this[i],i].concat(args));
if(res != null) a.push(res);
}
return a;
};

/**
* Get a collection of non-repeating elements in an array

* Unique an array
* @returns {Array} An array composed of non-repeating elements
*/
Array.prototype.uniquelize = function(){
var ra = new Array();
for(var i = 0; i < this.length; i ){
if(!ra.contains(this[i])){
ra.push(this[i]);
}
}
return ra;
};

/**
* Find the complement of two sets
{%example
<script> <br>var a = [1,2,3,4]; <br>var b = [3,4 ,5,6]; <br>alert(Array.complement(a,b)); <br></script>
%}
* @param {Array} a set A
* @param {Array} b Set B
* @returns {Array} The complement of the two sets
*/
Array.complement = function(a, b){
return Array.minus(Array.union(a, b),Array.intersect(a, b));
};

/**
* Find the intersection of two sets
{%example
<script> <br>var a = [1,2,3,4]; <br>var b = [3,4, 5,6]; <br>alert(Array.intersect(a,b)); <br></script>
%}
* @param {Array} a set A
* @ param {Array} b Set B
* @returns {Array} The intersection of two sets
*/
Array.intersect = function(a, b){
return a.uniquelize().each(function(o){return b.contains(o) ? o : null});
};

/**
* Find the difference between two sets
{%example
<script> <br>var a = [1,2,3,4]; <br>var b = [3,4 ,5,6]; <br>alert(Array.minus(a,b)); <br></script>
%}
* @param {Array} a set A
* @param {Array} b Set B
* @returns {Array} The difference between the two sets
*/
Array.minus = function(a, b){
return a.uniquelize().each(function(o){return b.contains(o) ? null : o});
};

/**
* Find the union of two sets
{%example
<script> <br>var a = [1,2,3,4]; <br>var b = [3,4 ,5,6]; <br>alert(Array.union(a,b)); <br></script>
%}
* @param {Array} a set A
* @param {Array} b Set B
* @returns {Array} The union of two sets
*/
Array.union = function(a, b){
return a.concat(b).uniquelize();
};