Question

我在编码游戏的更正中看到了这行代码

const tC = readline().split(' ').map(x => +x);

我想知道它是做什么的，因为当我登录此功能时，它会呈现与此功能相同的东西

const tC = readline().split(' ').map(x => x);

但其余代码无效

上下文：

/** Temperatures (easy) https://www.codingame.com/training/easy/temperatures
 * Solving this puzzle validates that the loop concept is understood and that
 * you can compare a list of values.
 * This puzzle is also a playground to experiment the concept of lambdas in
 * different programming languages. It's also an opportunity to discover
 * functional programming.
 *
 * Statement:
 * Your program must analyze records of temperatures to find the closest to
 * zero.
 *
 * Story:
 * It's freezing cold out there! Will you be able to find the temperature
 * closest to zero in a set of temperatures readings?
**/
const N = +readline();
const tC = readline().split(' ').map(x => +x);

let min = Infinity;

for (let i in tC) {
    (Math.abs(tC[i]) < Math.abs(min) || tC[i] === -min && tC[i] > 0) && (min = tC[i]);
}

print(min || 0);

非常感谢

Answer 1

.map(x => +x)将数组中的所有项目转换为数字。并返回具有这些转换后值的新数组。

如果将其更改为.map(x => x)，则这些值将保持不变，而您只需创建原始数组的副本即可。因此，字符串仍然是字符串，如果需要数字，则会破坏代码。

我个人会避免使用+x语法，而使用更冗长的Number(x)，而写.map(x => Number(x))或.map(Number)。

Answer 2

根据下面的site，是程序应接收的输入

第1行：N，要分析的温度数

第2行：N个温度的字符串表示为-273至5526之间的整数

让我逐行提供有关游戏规则的评论

// Line 1: reads number temperature inputs. + converts to number
const N = +readline();
// Line 2: reads string of temperatures.
// tC contains an array of temperatures of length N in numbers. + converts to number
const tC = readline().split(' ').map(x => +x);

let min = Infinity;
// iterate over tC array
for (let i in tC) {
    // If two numbers are equally close to zero, positive integer has to be considered closest to zero
    // set min = current iterating number if it matches above condition
    (Math.abs(tC[i]) < Math.abs(min) || tC[i] === -min && tC[i] > 0) && (min = tC[i]);
}

print(min || 0);

这是使用javascript的有效演示

进行了修改，以使初学者可以理解。

// Line 1: reads number temperature inputs. + converts to number
// const N = +readline(); SAMPLE ALTERNATIVE
const N = +"5";
// Line 2: reads string of temperatures.
// tC contains an array of temperatures of length N in numbers. + converts to number
// const tC = readline().split(' ').map(x => +x); SAMPLE ALTERNATIVE
const tC = "1 -2 -8 4 5".split(' ').map(x => +x);

let min = Infinity;
// iterate over tC array
for (let i in tC) {
    // If two numbers are equally close to zero, positive integer has to be considered closest to zero
    // set min = current iterating number if it matches above condition
    (Math.abs(tC[i]) < Math.abs(min) || tC[i] === -min && tC[i] > 0) && (min = tC[i]);
}

console.log(min || 0);

Answer 3

function readLine(){
  return "123456"
}

var result = readLine().split("").map(x => +x)

console.log(result)

readLine().split("") // 将字符串按如下所示拆分为数组[“ 1”，“ 2”，“ 3”，“ 4”，“ 5”，“ 6”]

.map(x => +x) // map方法返回一个新数组，该数组将接受每个项目并提供一个新数组，此处数字从字符串更改为数字，如下所示[1、2、3， 4，5，6]，因为使用了+ x

// 以上内容是用es6编写的，可以用es5编写，如下所示

readLine().split("").map(function(x) {
  return +x
})

// 注意

在es6中，如果只有一件事情要传递，我们可以避免将函数（x）传递给x

我们也可以删除{} [花括号并返回] {return +x}至+x

ES2015

readLine().split("").map(function(x) {
  return +x
})

ES2016

readLine().split("").map(x => +x);

我想知道这个函数实际上是做什么的.split（''）.map（x => + x）;

3 个答案:

这是使用javascript的有效演示