反向与反向！(Reverse vs Reverse! in Ruby when comparing palindrome)

反向与反向！(Reverse vs Reverse! in Ruby when comparing palindrome)

我知道reverse会创建一个新的字符串，并且字符串的字符反向并且相反！ 突变（反转）当前的字符串。 我的问题是为什么，例如测试回文时，会发生这种情况？

a = "foobar" a == a.reverse # => false a == a.reverse! # => true

是因为它在内存中是相同的对象，因此==只是检查它们是否具有相同的内存位置？

谢谢！

I know that reverse creates a new string with the characters of the string in reverse and that reverse! mutates (reverses) the current string in place. My question is why, when for example testing for a palindrome, this occurs?:

a = "foobar" a == a.reverse # => false a == a.reverse! # => true

Is it because it is the same object in memory, therefore == just checks if they have the same memory location?

Thanks!

最满意答案

String#reverse! 方法返回它所调用的字符串

a == a.reverse!

就像说的一样

a.reverse! a == a

当然a == a是真的。

请注意，至少reverse!并不重要reverse! 对字符串做了什么，重要的是在o == om是方法（ m ）返回的内容。

The String#reverse! method returns the string it is called on so

a == a.reverse!

is the same as saying

a.reverse! a == a

and of course a == a is true.

Note that it doesn't matter in the least what reverse! does to the string, what matters to == in o == o.m is what the method (m) returns.