阵列＃每个执行用于数组中的每个元素的给定块，然后返回数组本身。

Array#each executes the given block for each element of the array, then returns the array itself.

阵列＃地图也执行了数组的每个元素的给定块，但返回一个新的数组，其值是块的每个迭代的返回值。

Array#map also executes the given block for each element of the array, but returns a new array whose values are the return values of each iteration of the block.

例如：假设你有一个数组定义正是如此：

Example: assume you have an array defined thusly:

arr = ["tokyo", "london", "rio"]

然后尝试执行每个：

arr.each { |element| element.capitalize }
# => ["tokyo", "london", "rio"]

请注意返回的值就是同一阵列。里面的code中的每个块被执行，但不返回的计算值;而作为code有没有副作用，这个例子不执行有用的工作。

Note the return value is simply the same array. The code inside the each block gets executed, but the calculated values are not returned; and as the code has no side effects, this example performs no useful work.

在此相反，调用数组的地图方法返回一个新的数组，其元素是每一轮执行地图中的返回值块：

In contrast, calling the array's map method returns a new array whose elements are the return values of each round of executing the map block:

arr.map { |element| element.capitalize }
# => ["Tokyo", "London", "Rio"]