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  • JS求数组的交集、差集、并集、补集

    一、ES5

    1,直接使用 filter、concat 来计算

     1 var a = [1,2,3,4,5]
     2 var b = [2,4,6,8,10]
     3 //交集
     4 var c = a.filter(function(v){ return b.indexOf(v) > -1 })
     5 //差集
     6 var d = a.filter(function(v){ return b.indexOf(v) == -1 })
     7 //补集
     8 var e = a.filter(function(v){ return !(b.indexOf(v) > -1) })
     9  .concat(b.filter(function(v){ return !(a.indexOf(v) > -1)}))
    10 //并集
    11 var f = a.concat(b.filter(function(v){ return !(a.indexOf(v) > -1)}));
    12 console.log("数组a:", a);
    13 console.log("数组b:", b);
    14 console.log("a与b的交集:", c);
    15 console.log("a与b的差集:", d);
    16 console.log("a与b的补集:", e);
    17 console.log("a与b的并集:", f);

    2,对 Array 进行扩展

     1 //数组功能扩展
     2 //数组迭代函数
     3 Array.prototype.each = function(fn){
     4  fn = fn || Function.K;
     5  var a = [];
     6  var args = Array.prototype.slice.call(arguments, 1);
     7  for(var i = 0; i < this.length; i++){
     8  var res = fn.apply(this,[this[i],i].concat(args));
     9  if(res != null) a.push(res);
    10  }
    11  return a;
    12 };
    13 //数组是否包含指定元素
    14 Array.prototype.contains = function(suArr){
    15  for(var i = 0; i < this.length; i ++){
    16  if(this[i] == suArr){
    17  return true;
    18  }
    19  }
    20  return false;
    21 }
    22 //不重复元素构成的数组
    23 Array.prototype.uniquelize = function(){
    24  var ra = new Array();
    25  for(var i = 0; i < this.length; i ++){
    26  if(!ra.contains(this[i])){
    27  ra.push(this[i]);
    28  }
    29  }
    30  return ra;
    31 };
    32 //两个数组的交集
    33 Array.intersect = function(a, b){
    34  return a.uniquelize().each(function(o){return b.contains(o) ? o : null});
    35 };
    36 //两个数组的差集
    37 Array.minus = function(a, b){
    38  return a.uniquelize().each(function(o){return b.contains(o) ? null : o});
    39 };
    40 //两个数组的补集
    41 Array.complement = function(a, b){
    42  return Array.minus(Array.union(a, b),Array.intersect(a, b));
    43 };
    44 //两个数组并集
    45 Array.union = function(a, b){
    46  return a.concat(b).uniquelize();
    47 };
    48 //使用
    49 var a = [1,2,3,4,5]
    50 var b = [2,4,6,8,10]
    51 console.log("数组a:", a);
    52 console.log("数组b:", b);
    53 console.log("a与b的交集:", Array.intersect(a, b));
    54 console.log("a与b的差集:", Array.minus(a, b));
    55 console.log("a与b的补集:", Array.complement(a, b));
    56 console.log("a与b的并集:", Array.union(a, b));

    二、ES6

     1 var a = [1,2,3,4,5]
     2 var b = [2,4,6,8,10]
     3 console.log("数组a:", a);
     4 console.log("数组b:", b);
     5 var sa = new Set(a);
     6 var sb = new Set(b);
     7 // 交集
     8 let intersect = a.filter(x => sb.has(x));
     9 // 差集
    10 let minus = a.filter(x => !sb.has(x));
    11 // 补集
    12 let complement = [...a.filter(x => !sb.has(x)), ...b.filter(x => !sa.has(x))];
    13 // 并集
    14 let unionSet = Array.from(new Set([...a, ...b]));
    15 console.log("a与b的交集:", intersect);
    16 console.log("a与b的差集:", minus);
    17 console.log("a与b的补集:", complement);
    18 console.log("a与b的并集:", unionSet);

    三、Jquery

     1 var a = [1,2,3,4,5]
     2 var b = [2,4,6,8,10]
     3 console.log("数组a:", a);
     4 console.log("数组b:", b);
     5 // 交集
     6 let intersect = $(a).filter(b).toArray();
     7 // 差集
     8 let minus = $(a).not(b).toArray();
     9 // 补集
    10 let complement = $(a).not(b).toArray().concat($(b).not(a).toArray());
    11 // 并集
    12 let unionSet = $.unique(a.concat(b));
    13 console.log("a与b的交集:", intersect);
    14 console.log("a与b的差集:", minus);
    15 console.log("a与b的补集:", complement);
    16 console.log("a与b的并集:", unionSet);
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  • 原文地址:https://www.cnblogs.com/guanghe/p/14254400.html
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