我想使用不同的语法以方便调试。为什么它不起作用？

Question

这是一个我无法解决的问题，它来自codingGame。我看到了一个解决方案，但我尝试使用不同的语法以便更好地理解。

上下文

/** Horse Racing Duals (easy) https://www.codingame.com/training/easy/horse-racing-duals
 * This puzzle shows that sometimes, the simplest solution is not performant
 * enough. You will also learn to handle large arrays and gain experience
 * with their processing time.
 *
 * STATEMENT:
 * In this problem you have to find the two numbers that are closest to each
 * other among a list of numbers. The list might be really large and force
 * you to search for the best possible algorithmic complexity for your
 * solution.
 *
 * STORY:
 * To make a race between two horses interesting, you will have to find the
 * horses with the closest strength.
**/
print(
    new Array(+readline())
        .fill()             
        .map(() => +readline())   
        .sort((a, b) => a > b)
        .map((x, i, arr) => Math.abs(x - arr[i + 1])) 
        .sort((a, b)  => a > b) [0] 
);

为什么我不能这样做：

let tab = new Array(+readline())
tab.fill()
tab.map(() => +readline())
tab.sort((a, b) => a > b)
tab.map((x, i, arr) => Math.abs(x - arr[i + 1])) 
tab

Answer 1

Why can't I do this:

因为某些 map 方法 return 是一个新数组，而不是就地进行更改。

在您的示例中，仅 sort 就地改变数组，因此您的代码实际上等同于：

let tab = new Array(+readline())
tab.sort((a, b) => a > b)

请注意，sort 回调应该是 return 正数、负数或 0。 It should not return a Boolean.

Answer 2

为了使其相同，当方法未就地发生变化时，需要重新分配制表符。像这样：

let tab = new Array(+readline())
tab.fill()
tab = tab.map(() => +readline())
tab.sort((a, b) => a > b)
tab = tab.map((x, i, arr) => Math.abs(x - arr[i + 1])) 
print(tab)

我想使用不同的语法以方便调试。为什么它不起作用？

I would like to use a different syntax in order to facilitate debugging. Why doesn't it work?

javascript

ecmascript-6

array.prototype.map