Ruby，从字符串中删除最后 N 个字符? [英] Ruby, remove last N characters from a string?

问题描述

从字符串中删除最后 n 个字符的首选方法是什么?

What is the preferred way of removing the last n characters from a string?

推荐答案

Ruby 2.5+

从 Ruby 2.5 开始，您可以使用 delete_suffix 或 delete_suffix! 以快速且可读的方式实现这一点.

Ruby 2.5+

As of Ruby 2.5 you can use delete_suffix or delete_suffix! to achieve this in a fast and readable manner.

有关方法的文档在这里.

如果你知道后缀是什么，这是惯用的(我认为，比这里的其他答案更具可读性):

If you know what the suffix is, this is idiomatic (and I'd argue, even more readable than other answers here):

'abc123'.delete_suffix('123')     # => "abc"
'abc123'.delete_suffix!('123')    # => "abc"

它甚至比最佳答案快得多(使用 bang 方法几乎 40%).以下是相同基准测试的结果:

It's even significantly faster (almost 40% with the bang method) than the top answer. Here's the result of the same benchmark:

                     user     system      total        real
chomp            0.949823   0.001025   0.950848 (  0.951941)
range            1.874237   0.001472   1.875709 (  1.876820)
delete_suffix    0.721699   0.000945   0.722644 (  0.723410)
delete_suffix!   0.650042   0.000714   0.650756 (  0.651332)

我希望这很有用 - 请注意，该方法目前不接受正则表达式，因此如果您不知道后缀，则暂时不可行.但是，由于接受的答案(更新:撰写本文时)规定相同，我认为这可能对某些人有用.

I hope this is useful - note the method doesn't currently accept a regex so if you don't know the suffix it's not viable for the time being. However, as the accepted answer (update: at the time of writing) dictates the same, I thought this might be useful to some people.

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