Ruby中为何要同时有to_s,to_str,inspect这三个函数？nil.inspect为何是“nil”

Question

ruby新手，求大侠指点一二。

Answer 1

First question:
to_s should be a widely existing method, and to_str should be String or a method that only a few classes have. Ruby does have many methods, https://ruby-china.org/topics/25311.

Second question:
The return type of inspect is string, which returns a human-readable representation of the current object. nil.inpsect returns "nil" 因为他就是返回 "nil", just look at the NilClass#inspect documentation.

Answer 2

A problem needs to be pointed out here, that is, nil跟其他语言中的null是不一样的，nil in Ruby is an object (not a class, it is an object of the NilClass class). This object is used in Ruby to represent without anything, but it is an object in itself .