ruby-on-rails - Ruby - 如何使用 sort_by 对一个数组与另一个数组进行排序？

Question

我想对第一个数组进行排序:

 filenames = ["z.pdf", "z.txt", "a.pdf", "z.rf", "a.rf","a.txt", "z.html", "a.html"]

通过以下文件的扩展名数组:

 extensions = ["html", "txt", "pdf", "rf"]

使用 sort_by。但是当我尝试时:

 filenames.sort_by { |x| extensions.index x.split('.')[1] }

我得到:

 ["a.html", "z.html", "z.txt", "a.txt", "a.pdf", "z.pdf", "z.rf", "a.rf"]

扩展名为“txt”和“rf”的文件名未排序。我试图弄清楚 sort_by 如何使用元组进行排序，但一直无法找到 sort_by 的源代码。

如何使用 sort_by 将一个数组按另一个数组排序？

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编辑:

结果应该是这样的:

["a.html", "z.html", "a.txt", "z.txt", "a.pdf", "z.pdf", "a.rf", "z.rf"]

Answer 1

按扩展数组的索引排序，然后是文件名:

filenames = ["z.pdf", "z.txt", "a.pdf", "z.rf", "a.rf","a.txt", "z.html", "a.html"]
extensions = ["html", "txt", "pdf", "rf"]

p sorted = filenames.sort_by{|fn| [extensions.index(File.extname(fn)[1..-1]), fn]} #[1..-1] chops off the dot
#=> ["a.html", "z.html", "a.txt", "z.txt", "a.pdf", "z.pdf", "a.rf", "z.rf"]