等效于Ruby中的Ruby的each_cons [英] Equivalent of Ruby's each_cons in JavaScript

问题描述

有人问了这个问题，要求提供多种语言，而不是javascript.

Ruby具有方法 Enumerable#each_cons 看起来像这样:

  puts(0..5).each_cons(2).to_a#[[0，1]，[1，2]，[2，3]，[3，4]，[4，5]]放(0..5).each_cons(3).to_a#[[1、2、3]，[2、3、4]，[3、4、5]] 

我如何在javascript中为 Array 使用类似的方法?

解决方案

以下是可以实现此功能的函数(ES6 +):

 //功能方法const eachCons =(array，num)=>{return Array.from({length:array.length-num + 1}，(_，i)=>array.slice(i，i + num))}//原型替代方法Array.prototype.eachCons = function(num){return Array.from({length:this.length-num + 1}，(_，i)=>this.slice(i，i + num))}const array = [0,1,2,3,4,5]const log = data =>console.log(JSON.stringify(data))日志(eachCons(array，2))日志(eachCons(array，3))日志(array.eachCons(2))log(array.eachCons(3)) 

您必须猜测所得数组的长度( n = length-num + 1 )，然后才能利用JavaScript的Enumerable#each_cons which look like that:

puts (0..5).each_cons(2).to_a
# [[0, 1], [1, 2], [2, 3], [3, 4], [4, 5]]
puts (0..5).each_cons(3).to_a
# [[1, 2, 3], [2, 3, 4], [3, 4, 5]]

How could I have a similar method in javascript for Array?

解决方案

Here is a function that will do it (ES6+):

// functional approach
const eachCons = (array, num) => {
    return Array.from({ length: array.length - num + 1 },
                      (_, i) => array.slice(i, i + num))
}

// prototype overriding approach
Array.prototype.eachCons = function(num) {
  return Array.from({ length: this.length - num + 1 },
                    (_, i) => this.slice(i, i + num))
}


const array = [0,1,2,3,4,5]
const log = data => console.log(JSON.stringify(data))

log(eachCons(array, 2))
log(eachCons(array, 3))

log(array.eachCons(2))
log(array.eachCons(3))

You have to guess the length of the resulting array (n = length - num + 1), and then you can take advantage of JavaScript's array.slice To get the chunks you need, iterating n times.

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