如何将数组的每个成员乘以javascript中的变量标量？

Question

I'm writing a code that multiply each item in array with a variable scalar ( 2**i)

a=[1, 2, 3, 4]
for (let i=0; i<a.length; i++) {
    let output = // 
}
console.log(output)   // **output = [1*(2**0), 2*(2**1), 3(2**2), 4(2**3)]**

Answer 1

You can use map same as :

 const a = [1, 2, 3, 4] const output = a.map((ele, index) => ele*(2**index)) console.log(output) // **output = [1*(2**0), 2*(2**1), 3(2**2), 4(2**3)]**

Answer 2

Just create an array out of the for and push the values.

 a = [1, 2, 3, 4]; output = []; for (let i = 0; i < a.length; i++) { output.push(a[i] * (2 ** i)); } console.log(output)