集合

一种包含不同元素的数据结构 数据是无序的，数据之间不可重复

集合的定义

• 空集合
• 集合相等
• 子集
• 交集
• 并集
• 补集

Set的类型实现

    function mySet() {
        this.dataStore = []
    }
    mySet.prototype = {
        add: function(data) {
            if(this.dataStore.indexOf(data)>-1) {
                return false
            } else {
                this.dataStore.push(data)
            }
        },
        remove: function(data) {
            var index = this.dataStore.indexOf(data)
            this.dataStore.splice(index, 1)
        },
        clear: function() {
            this.dataStore = []
        },
        show: function() {
            console.log(this.dataStore)
        }
    }
    var eg = new mySet()
    eg.add('KKKK')
    eg.add('ttttt')

其他的集合操作

• 判断是否属于这个set

contains: function(data) {
    if(this.dataStore.indexOf(data)>-1) {
        return true
    } else {
        return false
    }
}, 

• 并集

union = function(set) {
    console.log(Object.getPrototypeOf(set).constructor )
    if(Object.getPrototypeOf(set).constructor == 'mySet') {
        set.dataStore.forEach(item => {
            this.add(item)
        });
    } else {
        return false
    }
}

• 交集

intersect: function(set) {
    console.log(Object.getPrototypeOf(set).constructor )
    if(Object.getPrototypeOf(set).constructor == 'mySet') {
        var tempSet = new mySet()
        for(let i= 0; i< set.dataStore.length; i++) {
            var item = set.dataStore[i]
            if(this.contains(item)) {
                tempSet.add(item)
            }
        }
    }
    return tempSet
}

• 子集

subSet: function(set) {
    // console.log(Object.getPrototypeOf(set).constructor )
    let result = true
    if(Object.getPrototypeOf(set).constructor == 'mySet') {
        if(set.dataStore.length < this.dataStore.length) {
            set.dataStore.forEach(item => {
                console.log(item)
                if(!this.contains(item)) {
                    result = false
                }
            })
        } else {
            result = false
        }
    }
    return result
}

完整代码

function mySet() {
        this.dataStore = []
    }
    mySet.prototype = {
        constructor: 'mySet',
        add: function(data) {
            if(this.dataStore.indexOf(data)>-1) {
                return false
            } else {
                this.dataStore.push(data)
            }
        },
        remove: function(data) {
            var index = this.dataStore.indexOf(data)
            this.dataStore.splice(index, 1)
        },
        clear: function() {
            this.dataStore = []
        },
        show: function() {
            console.log(this.dataStore)
        },
        contains: function(data) {
            if(this.dataStore.indexOf(data)>-1) {
                return true
            } else {
                return false
            }
        }, 
        union: function(set) {
            console.log(Object.getPrototypeOf(set).constructor )
            if(Object.getPrototypeOf(set).constructor == 'mySet') {
                set.dataStore.forEach(item => {
                    this.add(item)
                });
            } else {
                return false
            }
        },
        intersect: function(set) {
            console.log(Object.getPrototypeOf(set).constructor )
            if(Object.getPrototypeOf(set).constructor == 'mySet') {
                var tempSet = new mySet()
                for(let i= 0; i< set.dataStore.length; i++) {
                    var item = set.dataStore[i]
                    if(this.contains(item)) {
                        tempSet.add(item)
                    }
                }
            }
            return tempSet
        },
        subSet: function(set) {
            // console.log(Object.getPrototypeOf(set).constructor )
            let result = true
            if(Object.getPrototypeOf(set).constructor == 'mySet') {
                if(set.dataStore.length < this.dataStore.length) {
                    set.dataStore.forEach(item => {
                        console.log(item)
                        if(!this.contains(item)) {
                            result = false
                        }
                    })
                } else {
                    result = false
                }
            }
            return result
        }
    }
    var eg = new mySet()
    eg.add('KKKK')
    eg.add('ttttt')
    var othereg = new mySet()
    othereg.add('other')
    othereg.add('KKKK')
    var subset = new mySet()
    subset.add('KKKK')