从索引为 1 到 5 的数组返回项目 Javascript

Question

我如何 console.log 当前数组中索引 1 到 5 的项目？ 使用循环

 let cars = ["AUDI","BMW","LEXUS","VOLKSWAGEN","FERRARY","PORSCHE"] const mappedCars=cars.map((item, i) => { console.log("The current index is: " + i); console.log("The current element is: " + item); console.log("\n"); return item; //equivalent to list[index] }); console.log(mappedCars);

Answer 1

使用 for 循环：

 let cars = ["AUDI","BMW","LEXUS","VOLKSWAGEN","FERRARY","PORSCHE"] for(i = 1; i<cars.length; i++){ console.log("The current index is: " + i); console.log("The current element is: " + cars[i]); console.log("\n"); };

Answer 2

要在索引 1 到 5（包括）的循环中执行此操作：

 let cars = ["AUDI","BMW","LEXUS","VOLKSWAGEN","FERRARY","PORSCHE"] const filteredCars = []; for (let i=1; i<=5; i++) { filteredCars.push(cars[i]); } console.log(filteredCars);

如果没有循环，您也可以使用filter()或slice() 。 请参阅filter()示例：

 let cars = ["AUDI","BMW","LEXUS","VOLKSWAGEN","FERRARY","PORSCHE"] const filteredCars=cars.filter((item, i) => i>=1 && i<=5); console.log(filteredCars);

Answer 3

使用for loop ，您可以定义初始条件以及循环终止条件。

for ([initialExpression]; [condition]; [incrementExpression])
 statement

let cars = ["AUDI","BMW","LEXUS","VOLKSWAGEN","FERRARY","PORSCHE"]

const updated = [];
for (let i=1; i<=5; i++) {
        updated.push(cars[i]);
}

console.log(updated);

Answer 4

你可以用forEach做到这一点：

 let cars = ["AUDI","BMW","LEXUS","VOLKSWAGEN","FERRARY","PORSCHE"]; function repea (element, index) { console.log(`The current index is: ${index}`); console.log(`The current element is: ${element}`); } cars.forEach(repea);