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实现列表类

// 列表类function List () {    this.listSize = 0; // 列表的元素个数    this.pos = 0; // 列表的当前位置    this.dataStore = []; // 初始化一个空数组来保存列表元素    this.clear = clear; // 清空列表中的所有元素    this.find = find;    this.toString = toString;    this.insert = insert;    this.append = append;    this.remove = remove;    this.front = front;    this.end = end;    this.prev = prev;    this.next = next;    this.hasNext = hasNext;    this.hasPrev = hasPrev;    this.length = length;    this.currPos = currPos; // 返回列表的当前位置    this.moveTo = moveTo;    this.getElement = getElement; // 返回当前位置的元素    this.contains = contains;}// append: 给列表添加元素function append (element) {    this.dataStore[this.listSize++] = element;}// find: 在列表中查找某一元素 indexOf?function find (element) {    for (let i = 0; i < this.dataStore.length; i++) {        if (this.dataStore[i] === element) {            return i;        }    }    return -1;}// remove: 从列表中删除元素function remove (element) {    let foundAt = this.find(element);    if (foundAt > -1) {        this.dataStore.splice(foundAt, 1);        this.listSize--;        return true;    }    return false;}// length: 列表中有多少个元素 与listSize区别?function length () {    return this.listSize;}// toString: 显示列表中的元素function toString () {    return this.dataStore;}// insert: 向列表中插入一个元素function insert (element, after) {    let insertPos = this.find(after);    if (insertPos > -1) {        this.dataStore.splice(insertPos + 1, 0, element);        this.listSize++;        return true;    }    return false;}// clear: 清空列表中所有的元素function clear () {    delete this.dataStore;    this.dataStore.length = 0;    this.listSize = this.pos = 0;}// contains: 判断给定值是否在列表中 find?function contains (element) {    for (let i = 0; i < this.dataStore.length; i++) {        if (this.dataStore[i] === element) {            return true;        }    }    return false;}// 遍历列表function front () {    this.pos = 0;}function end () {    this.pos = this.listSize - 1;}function prev () {    --this.pos;}function next () {    if (this.pos < this.listSize) {        ++this.pos;    }}function currPos () {    return this.pos;}function moveTo (position) {    this.pos = position;}function getElement () {    return this.dataStore[this.pos];}function hasNext () {    return this.pos < this.listSize;}function hasPrev () {    return this.pos >= 0;}

练习

一. 增加一个向列表中插入元素的方法，该方法只在待插元素大于列表中的所有元素时才执行插入操作。这里的大于有多重含义，对于数字，它是指数值上的大小；对于字母，它是指在字母表中出现的先后顺序。

List.prototype.insertThen = function (element) {    let type = typeof element;    if (type === `number`) {        // debugger;        for (let i = 0; i < this.dataStore.length; i++) {            if (typeof this.dataStore[i] === `number` && element > this.dataStore[i]) { // 同时满足是数字然后插入的元素大于数组内的元素                this.append(element);                return true;            }        }    } else {        let newArr = this.dataStore.filter((val) => {            return typeof val !== `number`;        }).concat([element]).sort();        if (newArr.indexOf(element) === (newArr.length - 1)) {            this.append(element);            return true;        }    }    return false;};// 示例let DataThen = new List();DataThen.append(`Mazey`);DataThen.append(`Cherrie`);DataThen.append(`Luna`);DataThen.append(`John`);DataThen.append(`July`);DataThen.append(23);DataThen.append(73);console.log(DataThen.toString()); // ["Mazey", "Cherrie", "Luna", "John", "July", 23, 73]DataThen.insertThen(99);DataThen.insertThen(12);console.log(DataThen.toString()); // ["Mazey", "Cherrie", "Luna", "John", "July", 23, 73, 99]DataThen.insertThen(`Jay`);DataThen.insertThen(`Zero`);console.log(DataThen.toString()); // ["Mazey", "Cherrie", "Luna", "John", "July", 23, 73, 99, "Zero"]

二. 增加一个向列表中插入元素的方法，该方法只在待插元素小于列表中的所有元素时才执行插入操作。

List.prototype.insertThen = function (element) {    let type = typeof element;    if (type === `number`) {        // debugger;        for (let i = 0; i < this.dataStore.length; i++) {            if (typeof this.dataStore[i] === `number` && element < this.dataStore[i]) { // 同时满足是数字然后插入的元素大于数组内的元素                this.append(element);                return true;            }        }    } else {        let newArr = this.dataStore.filter((val) => {            return typeof val !== `number`;        }).concat([element]).sort();        if (newArr.indexOf(element) === 0) {            this.append(element);            return true;        }    }    return false;};// 示例let DataThen = new List();DataThen.append(`Mazey`);DataThen.append(`Cherrie`);DataThen.append(`Luna`);DataThen.append(`John`);DataThen.append(`July`);DataThen.append(23);DataThen.append(73);console.log(DataThen.toString()); // ["Mazey", "Cherrie", "Luna", "John", "July", 23, 73]DataThen.insertThen(99);DataThen.insertThen(12);console.log(DataThen.toString()); // ["Mazey", "Cherrie", "Luna", "John", "July", 23, 73, 12]DataThen.insertThen(`Jay`);DataThen.insertThen(`Zero`);DataThen.insertThen(`Ada`);console.log(DataThen.toString()); // ["Mazey", "Cherrie", "Luna", "John", "July", 23, 73, 12, "Ada"]

三. 创建Person类，该类用于保存人的姓名和性别信息。创建一个至少包含10个Person对象的列表。写一个函数显示列表中所有拥有相同性别的人。

function Person () {    this.list = [];    this.save = save;    this.showSameGender = showSameGender;}// 保存人名和性别function save (name, gender) {    let littleCase = {        name,        gender    };    this.list.push(littleCase);}// 显示相同性别的人function showSameGender (gender) {    let ret = [];    let len = this.list.length;    while (len--) {        if (this.list[len].gender === gender) {            ret.push(this.list[len].name);        }    }    return ret;}// 示例let people = new Person();people.save(`Mazey`, `male`);people.save(`John`, `male`);people.save(`Zero`, `male`);people.save(`July`, `male`);people.save(`Bob`, `male`);people.save(`Ada`, `female`);people.save(`Cherrie`, `female`);people.save(`Luna`, `female`);people.save(`Lucy`, `female`);people.save(`June`, `female`);console.log(people.list);console.log(people.showSameGender(`male`)); // ["Bob", "July", "Zero", "John", "Mazey"]console.log(people.showSameGender(`female`)); // ["June", "Lucy", "Luna", "Cherrie", "Ada"]