javaScript基础学习 - 9 - JavaScript数组 - 案例代码
- 1. 数组的使用
- 2. 遍历数组
- 3. 数组长度
- 4. 计算数组的和以及平均值
- 5. 求数组中的最大值
- 6. 数组转换为字符串
- 7. 新增数组元素
- 8. 数组存放1~10个值
- 9. 筛选数组
- 10. 数组去重(删除指定数组元素)
- 11. 翻转数组
- 12. 冒泡排序
1. 数组的使用
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Documenttitle>
<script>
var arr = new Array();
var arr = [];
var arr1 = [1, 2, '小李子', true];
console.log(arr1);
console.log(arr1[2]);
console.log(arr1[3]);
var arr2 = ['迪丽热巴', '古丽扎娜', '佟丽丫丫'];
console.log(arr2[0]);
console.log(arr2[1]);
console.log(arr2[2]);
console.log(arr2[3]);
script>
head>
<body>
body>
html>
2. 遍历数组
<script>
var arr = ['red', 'green', 'blue'];
for (var i = 0; i < 3; i++) {
console.log(arr[i]);
}
script>
3. 数组长度
<script>
var arr = ['关羽', '张飞', '马超', '赵云', '黄忠', '刘备', '姜维', '小李子'];
for (var i = 0; i < 7; i++) {
console.log(arr[i]);
}
console.log(arr.length);
for (var i = 0; i < arr.length; i++) {
console.log(arr[i]);
}
script>
4. 计算数组的和以及平均值
<script>
var arr = [2, 6, 1, 7, 4];
var sum = 0;
var average = 0;
for (var i = 0; i < arr.length; i++) {
sum += arr[i];
}
average = sum / arr.length;
console.log(sum, average);
script>
5. 求数组中的最大值
<script>
var arr = [2, 6, 1, 77, 52, 25, 7, 99];
var max = arr[0];
for (var i = 1; i < arr.length; i++) {
if (arr[i] > max) {
max = arr[i];
}
}
console.log('该数组里面的最大值是：' + max);
script>
6. 数组转换为字符串
<script>
var arr = ['red', 'green', 'blue', 'yellow'];
var str = '';
var sep = '*';
for (var i = 0; i < arr.length; i++) {
str += arr[i] + sep;
}
console.log(str);
script>
7. 新增数组元素
<script>
var arr = ['red', 'green', 'blue'];
console.log(arr.length);
arr.length = 5;
console.log(arr);
console.log(arr[3]);
console.log(arr[4]);
var arr1 = ['red', 'green', 'blue'];
arr1[3] = 'pink';
console.log(arr1);
arr1[4] = 'hotpink';
console.log(arr1);
arr1[0] = 'yellow';
console.log(arr1);
arr1 = '有点意思';
console.log(arr1);
script>
8. 数组存放1~10个值
<script>
var arr = [];
for (var i = 0; i < 100; i++) {
arr[i] = i + 1;
}
console.log(arr);
script>
9. 筛选数组
<script>
var arr = [2, 0, 6, 1, 77, 0, 52, 0, 25, 7];
var newArr = [];
var j = 0;
for (var i = 0; i < arr.length; i++) {
if (arr[i] >= 10) {
newArr[j] = arr[i];
j++;
}
}
console.log(newArr);
var arr = [2, 0, 6, 1, 77, 0, 52, 0, 25, 7];
var newArr = [];
for (var i = 0; i < arr.length; i++) {
if (arr[i] >= 10) {
newArr[newArr.length] = arr[i];
}
}
console.log(newArr);
script>
10. 数组去重(删除指定数组元素)
<script>
var arr = [2, 0, 6, 1, 77, 0, 52, 0, 25, 7];
var newArr = [];
for (var i = 0; i < arr.length; i++) {
if (arr[i] != 0) {
newArr[newArr.length] = arr[i];
}
}
console.log(newArr);
script>
11. 翻转数组
<script>
var arr = ['red', 'green', 'blue', 'pink', 'purple', 'hotpink'];
var newArr = [];
for (var i = arr.length - 1; i >= 0; i--) {
newArr[newArr.length] = arr[i]
}
console.log(newArr);
script>
12. 冒泡排序
<script>
var arr = [4, 1, 2, 3, 5];
for (var i = 0; i <= arr.length - 1; i++) {
for (var j = 0; j <= arr.length - i - 1; j++) {
if (arr[j] < arr[j + 1]) {
var temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
console.log(arr);
script>
