我如何重写功能代码 javascript

Question

returns a new array 包含 each pair of numbers 来自具有 相同索引 的参数的乘积的函数。

var a = [3, 5, 7];
var b = [9, 10, 11];

a.map(function(x, index) { //here x = a[index] //how do i write this as function name(){}
  console.log(b[index] * x);
});

Answer 1

这样

var a = [3, 5, 7];
var b = [9, 10, 11];

function myFunction(x,index)
  {
  return (b[index] * x);
  }

var c = a.map(myFunction);

console.log( c )

Answer 2

var a = [3, 5, 7];
var b = [9, 10, 11];

let c = [];

function name(a, b) {
    a.map(function(x, index) {
         let result = b[index] * x;
         c.push(result);
     }
}

name(a, b);
console.log(c) // this will show a new array with the results

Answer 3

您需要 return 来自 map 回调的新值。

var a = [3, 5, 7];
var b = [9, 10, 11];

const res = a.map((x,index)=>b[index] * x);
console.log(res);

Answer 4

.map() 的规格说明：

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.

var a = [3, 5, 7];
var b = [9, 10, 11];

function name(value_of_array_a, index_of_array_b) {
  return b[index_of_array_b] * value_of_array_a;
} 

var result = a.map(name);
console.log(result);

我如何重写功能代码 javascript

How do i rewriting a function code javascript

javascript

arrays

function

array.prototype.map