試圖找到一個數組中的素數

Question

我想從數組中刪除非素數，以下是僅刪除偶數而不是質數。

function sumPrimes(num) { 
    //Produce an array containing all number of to and including num 
    let numArray = []; 
    for (let i = 1; i <= num; i++) { 
    numArray.push(i); 
    } 

    //Remove non-prime numbers from the array  
    numArray.map((number) => { 
    for (let i = 2; i < number; i++) { 
     if(number % i === 0) { 
      let index = numArray.indexOf(number); 
      return numArray.splice(index, 1);  
     } 
    } 
    }); 

return numArray; 

} 

sumPrimes(10); 

這是目前返回：

[1, 2, 3, 5, 7, 9] 

然而，素數是1，2，3，5，7（不包括9）;

Answer 1

使用filter()代替：

var numArray = [2, 3, 4, 5, 6, 7, 8, 9, 10] 
 

 
numArray = numArray.filter((number) => { 
 
    for (var i = 2; i <= Math.sqrt(number); i++) { 
 
    if (number % i === 0) return false; 
 
    } 
 
    return true; 
 
}); 
 

 
console.log(numArray);