Array.sort！{| element | Array.count（element）}有什么作用？

Question

我想按照它们出现在数组中的频率对数组中的一些字符串进行排序。我知道我可以使用sort_by来实现这一点，但我偶然使用了这段代码 items.sort！{| x | items.count（x）} 并想知道列表发生了什么。< / p>

items = ["apple", "pineapple", "apple", "apple", "orange", "orange", "grape"]
items.sort!{|x|items.count(x)}
items = ["grape", "apple", "apple", "orange", "apple", "orange", "pineapple"]

items = ["apple", "pineapple", "apple", "apple", "orange", "orange", "grape", "pineapple", "apple", "orange"]
items.sort!{|x|items.count(x)}
items = ["orange", "orange", "apple", "grape", "apple", "pineapple", "orange", "apple", "apple", "pineapple"]