javascript奇怪的控制台日志

Question

我有一个 make 函数赋值给你一个排序数组，其中包含从 1 到 45 的 6 个随机数。所有数组值都不应彼此相等。

我想过一个可以在 Java 中运行的解决方案，但我得到的 JavaScript 控制台日志非常困惑。谁能帮帮我？

"use strict";

var numbers = [];
for(var x = 1; x <46;x++){
    numbers.push(x);
}


function LottoTipp(){
    var result = [];

    for(var i = 0; i <6; i++){
      var randomNum = Math.round(Math.random()* 45);
      var pushed = numbers[randomNum];
      result.push(pushed);
      numbers.splice(randomNum)
    }

    return console.log(result) + console.log(numbers);

}

LottoTipp(); 

控制台日志

[ 34, 7, undefined, undefined, undefined, undefined ]

[ 1, 2, 3, 4, 5, 6 ]

Answer 1

There were three problems:

• If you want to remove one item of an array you have to splice it by the items index and give a deletecount.

  In your case: numbers.splice(randomNum, 1);

• You have to use Math.floor instead of Math.round, because Math.floor always down to the nearest integerer, while Math.round searches for the nearest integer wich could be higher than numbers.length.

• After removing one item the length of the array has been changed. So you have to multiply by numbers.lenght instead of 45.

  In your case: var randomNum = Math.floor(Math.random()* numbers.length);

"use strict";

var numbers = [];
for(var x = 1; x < 46; x++){
    numbers.push(x);
}


function LottoTipp(){
    var result = [];

    for(var i = 0; i < 6; i++){
      var randomNum = Math.floor(Math.random()* numbers.length);
      var pushed = numbers[randomNum];
      result.push(pushed);
      numbers.splice(randomNum, 1);
    }

    return console.log(result) + console.log(numbers);

}

LottoTipp();