Ruby:在字符处拆分字符串，从右侧开始计数 [英] Ruby: Split string at character, counting from the right side

问题描述

简短版本——如何在 ruby​​ 中执行 Python rsplit()?

Short version -- How do I do Python rsplit() in ruby?

更长的版本 -- 如果我想在第一个 '.' 处将字符串分成两部分(名称、后缀)性格，这很好地完成了工作:

Longer version -- If I want to split a string into two parts (name, suffix) at the first '.' character, this does the job nicely:

name, suffix = name.split('.', 2)

但是如果我想在最后(最右边)分割'.'性格，我想不出比这更优雅的东西了:

But if I want to split at the last (rightmost) '.' character, I haven't been able to come up with anything more elegant than this:

idx = name.rindex('.')
name, suffix = name[0..idx-1], name[idx+1..-1] if idx

注意原来的名字字符串可能根本没有点，在这种情况下名字应该保持不变，后缀应该为零；它也可能有多个点，在这种情况下，只有最后一个点之后的位才是后缀.

Note that the original name string may not have a dot at all, in which case name should be untouched and suffix should be nil; it may also have more than one dot, in which case only the bit after the final one should be the suffix.

推荐答案

String#rpartition 就是这样做的:

String#rpartition does just that:

name, match, suffix = name.rpartition('.')

它是在 Ruby 1.8.7 中引入的，因此如果运行早期版本，您可以使用 require 'backports/1.8.7/string/rpartition' 使其工作.

It was introduced in Ruby 1.8.7, so if running an earlier version you can use require 'backports/1.8.7/string/rpartition' for that to work.

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