js中数组添加元素的方法(js数组里面放键值对)

今天,我们来一起学习一下如何把元素添加到元素的首个元素。

1.Array.unshift()

letfruits=["Apple","Banana","Mango"];

fruits.unshift("Orange");
console.log(fruits);
//Prints["Orange","Apple","Banana","Mango"]
fruits.unshift("Guava","Papaya");
console.log(fruits);
//Prints["Guava","Papaya","Orange","Apple","Banana","Mango"]

2.使用展开运算符(…)

varfruits=["Apple","Banana","Mango"];

varmoreFruits=["Orange",...fruits];
console.log(moreFruits);
//Prints["Orange","Apple","Banana","Mango"]
varsomeoMoreFruits=["Guava","Papaya",...moreFruits];
console.log(someoMoreFruits);
//Prints["Guava","Papaya","Orange","Apple","Banana","Mango"]
console.log(fruits);
//Prints["Apple","Banana","Mango"]

3.使用 Array.concat()

我们还可以使用concat()方法在开头连接两个(或更多)数组。

varfruits=["Apple","Banana","Mango"];
varmoreFruits=["Orange"];
varsomeoMoreFruits=["Guava","Papaya"];

varallFruits=someoMoreFruits.concat(moreFruits,fruits);
console.log(allFruits);
//Prints["Guava","Papaya","Orange","Apple","Banana","Mango"]

完~我是小智,我要去刷碗了,我们下期再见~

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