JavaScript | 数组的常用属性和方法

JavaScript的通用属性和数组方法 (Common properties and methods of array in JavaScript )

Properties/Methods	Descriptions
array.length	Returns the length of the array/total number of elements of the array
array[index]	Returns the item name stored at “index” position
array.push(item)	Inserts item at the end of the array
array.unshift(item)	Inserts item at the front of the array
array.pop()	Removes item from the end of the array
array.shift()	Removes item from the end of the array
array.indexOf(item)	Returns the index of the item
array.splice(index,1))	Removes item from the list (index must be provided)

属性/方法	内容描述
array.length	返回数组的长度/数组中元素的总数
数组[索引]	返回存储在“索引”位置的项目名称
array.push(item)	在数组末尾插入项目
array.unshift(项目)	在数组的前面插入项目
array.pop()	从数组末尾删除项目
array.shift()	从数组末尾删除项目
array.indexOf(item)	返回项目的索引
array.splice(index，1))	从列表中删除项目(必须提供索引)

Code:

码：

<html>
<head>
<script>
var fruits = [
"apple",
"mango",
"banana",
"grapes",
"guava"
];
</script>
</head>
<body>
<script>
document.write("<h3>List Of Array Items</h3>")
document.write("<hr />");
document.write("<ul>");
for(var i=0;i<fruits.length;i++){
document.write("<li>"+fruits[i]+"</li>");
}
document.write("</ul>");
document.write("<hr />")
var size=fruits.length;
document.write("Size of Array : "+size+"<br />");
var first = fruits[0];
document.write("First Item of Array : "+first+"<br /><br />");
fruits.forEach(function(item,index,array){
document.write("Fruits["+index+"] = "+item+"<br />");
});
//Insert Item at last
fruits.push("orange");
document.write("<br />")
fruits.forEach(function(item,index,array){
document.write("Fruits["+index+"] = "+item+"<br />");
});
//Insert Item at Front
fruits.unshift("cherry");
document.write("<br />")
fruits.forEach(function(item,index,array){
document.write("Fruits["+index+"] = "+item+"<br />");
});
//Remove Item from Last
fruits.pop();
document.write("<br />")
fruits.forEach(function(item,index,array){
document.write("Fruits["+index+"] = "+item+"<br />");
});
//Remove Item from Front
fruits.shift();
document.write("<br />")
fruits.forEach(function(item,index,array){
document.write("Fruits["+index+"] = "+item+"<br />");
});
//Finding Index of Item
var index = fruits.indexOf("banana");
document.write("<br />");
document.write("Index of banana : "+index+"<br />");
//Removing any item from List
document.write("<br />");
var pos = fruits.indexOf("banana");
fruits.splice(pos,1)
fruits.forEach(function(item,index,array){
document.write("Fruits["+index+"] = "+item+"<br />");
});
</script>
</body>
</html>

Output

输出量

List Of Array Items
apple
mango
banana
grapes
guava
Size of Array : 5
First Item of Array : apple
Fruits[0] = apple
Fruits[1] = mango
Fruits[2] = banana
Fruits[3] = grapes
Fruits[4] = guava
Fruits[0] = apple
Fruits[1] = mango
Fruits[2] = banana
Fruits[3] = grapes
Fruits[4] = guava
Fruits[5] = orange
Fruits[0] = cherry
Fruits[1] = apple
Fruits[2] = mango
Fruits[3] = banana
Fruits[4] = grapes
Fruits[5] = guava
Fruits[6] = orange
Fruits[0] = cherry
Fruits[1] = apple
Fruits[2] = mango
Fruits[3] = banana
Fruits[4] = grapes
Fruits[5] = guava
Fruits[0] = apple
Fruits[1] = mango
Fruits[2] = banana
Fruits[3] = grapes
Fruits[4] = guava
Index of banana : 2
Fruits[0] = apple
Fruits[1] = mango
Fruits[2] = grapes
Fruits[3] = guava