Java Script 循环,数组,对象,判断,阶乘,查找-综合运用合集

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所属分类:Web前端
摘要

 输出100个hello world. 创建一个包含1~100的数组. 定义一个数组,遍历输出它的每一项.

 

  1. 输出100个hello world.

    for (var i = 1; i <= 100; i++) {
    console.log("hello world");
    }
  2. 创建一个包含1~100的数组.

    var array = [];
    for (var i = 1; i <= 100; i++) {
    array.push(i);
    }
    console.log(array);
  3. 定义一个数组,遍历输出它的每一项.

    var array = [55, 45, 77, 88, 99, 101, 120];
    for (var i = 0; i < array.length; i++) {
    console.log(array[i]);
    }
  4. 输出1-100的所有奇数.

    for (var i = 1; i < 100; i++) {
    if (i % 2 !== 0) {
    console.log(i);
    }
    }
  5. 定义一个数组,输出数组中所有的奇数.

    var array = [44, 55, 23, 45, 77, 88];
    for (var i = 0; i < array.length; i++) {
    if (array[i] % 2 !== 0) {
    console.log(array[i]);
    }
    }
  6. 定义一个数组,找出所有的奇数,放入到一个新数组中.

    var array1 = [44, 55, 23, 45, 77, 8];
    var array2 = [];
    for (var i = 0; i < array1.length; i++) {
    if (array1[i] % 2 !== 0) {
    array2.push(array1[i]);
    }
    }
    console.log(array2);
  7. 1~100求和.

    var sum = 0;
    for (var i = 1; i <= 100; i++) {
    sum += i;
    }
    console.log(sum);
  8. 求某个数的阶乘.

    function factorial(n) {
    var result = 1;
    if (n < 1) {
    return 0;
    }
    for (var i = 1; i <= n; i++) {
    result *= i;
    }
    return result;
    }
    console.log(factorial(5));
  9. 数组求和.

    sum = 0;
    var array = [1, 2, 3, 4, 5];
    for (var i = 0; i <= array.length; i++) {
    sum += i;
    }
    console.log(sum);
  10. 求数组中的奇数的个数.

    var count = 0;
    var array = [1, 2, 3, 4, 6];
    for (var i = 0; i < array.length; i++) {
    if (array[i] % 2 !== 0) {
    count++;
    }
    }
    console.log(count);
  11. 求数组中的奇数和.

    var sum = 0;
    var array = [1, 2, 3, 4, 7];
    for (var i = 0; i < array.length; i++) {
    if (array[i] % 2 !== 0) {
    sum = sum + array[i];
    }
    }
    console.log(sum);
  12. 数组中是否存在某个数,输出 是 或 否.

    var array = [77, 88, 66, 54, 32, 21, 1];
    var target = 1;
    var isFind = false;
    for (var i = 0; i < array.length; i++) {
    if (array[i] === target) {
    isFind = true;
    break;
    }
    }
    if ((isFind = true)) {
    console.log("是");
    } else {
    console.log("否");
    }
  13. 数组中是否存在某个数,如果存在,则输出它所在的下标,如果不存在,则输出-1.

    var array = [99, 55, 34, 25, 77, 65, 32];
    var target = 65;
    var index = -1;
    for (var i = 0; i < array.length; i++) {
    if (array[i] === target) {
    index = i;
    break;
    }
    }
    console.log(index);
    var array = [1, 2, 3, 477, 54, 88, 65];
    for (var i = 0; i < array.length; i++) {
    console.log(i);
    }
  14. 找到数组中第一个奇数和最后一个奇数,将它们求和.

    var array = [55, 44, 65, 1, 2, 7, 15];
    var sum = 0;
    var isFind = false;
    for (var i = 0; i < array.length; i++) {
    if (array[i] % 2 !== 0) {
    isFind = array[i];
    }
    }
    var last = false;
    for (var i = array.length - 1; i >= 0; i--) {
    if (array[i] % 2 !== 0) {
    last = array[i];
    }
    sum = isFind + last;
    }
    console.log(isFind, last, sum);
  15. 有两个数组,看两个数组中是否都存在奇数,输出 是 或 否.

    var array1 = [4, 44, 7, 10, 8, 22, 12];
    var array2 = [22, 80, 22, 31];
    var isFind1 = false;
    var isFind2 = false;
    for (var i = 0; i < array1.length; i++) {
    if (array1[i] % 2 !== 0) {
    isFind1 = array1[i];
    break;
    }
    }
    for (var i = 0; i < array2.length; i++) {
    if (array2[i] % 2 !== 0) {
    isFind2 = array2[i];
    break;
    }
    }
    if (isFind1 && isFind2) {
    console.log("是");
    } else {
    console.log("否");
    }
  16. 输出一个对象的所有键值对.

    var obj = {
    a: 23,
    c: "jk",
    p: "75",
    };
    for (var key in obj) {
    console.log(key + "=" + obj[key]);
    }
  17. 计算对象中字符串属性的数量.

    var obj = {
    a: "55",
    jk: "45",
    oppo: "54",
    txp: 5,
    };
    var count = 0;
    for (var key in obj) {
    if (typeof obj[key] === "string") {
    count++;
    }
    }
    console.log(count);
  18. 将一个对象所有的数字属性,转换为字符串,并在其前面加上¥.

    var obj = {
    name: "xxx",
    balance: 199.8,
    taken: 3000,
    };
    var newobj = {};
    for (var key in obj) {
    var velue = obj[key];
    if (typeof velue === "number") {
    newobj[key] = "¥" + velue;
    } else {
    newobj[key] = velue;
    }
    }
    console.log(obj, newobj);