排序字符串在Ruby中的数组 [英] Sorting an array of strings in Ruby

问题描述

我已经在Ruby中得知两数组排序方法：

I have learned two array sorting methods in Ruby:

array = ["one", "two", "three"]
array.sort.reverse!

或

array = ["one", "two", "three"]
array.sort { |x,y| y<=>x }

和我不能够在两者之间进行区分。哪种方法更好，究竟如何在执行不同？

And I am not able to differentiate between the two. Which method is better and how exactly are they different in execution?

推荐答案

这两条线做同样的（创建新阵列，这是反向排序）。主要论点是关于可读性和性能。 <！code> array.sort.reverse 比 {的Array.sort更具可读性| X，Y | Y'LT =方式＆gt; X} - 我认为，我们可以在这里同意

Both lines do the same (create a new array, which is reverse sorted). The main argument is about readability and performance. array.sort.reverse! is more readable than array.sort{|x,y| y<=>x} - I think we can agree here.

有关业绩的一部分，我创建了一个快速基准脚本，它给我的系统上的以下（红宝石1.9.3p392 [x86_64的Linux的] ）：

For the performance part, I created a quick benchmark script, which gives the following on my system (ruby 1.9.3p392 [x86_64-linux]):

                              user     system      total        real
array.sort.reverse        1.330000   0.000000   1.330000 (  1.334667)
array.sort.reverse!       1.200000   0.000000   1.200000 (  1.198232)
array.sort!.reverse!      1.200000   0.000000   1.200000 (  1.199296)
array.sort{|x,y| y<=>x}   5.220000   0.000000   5.220000 (  5.239487)

运行时间为基准脚本的多个执行pretty不变。

Run times are pretty constant for multiple executions of the benchmark script.

array.sort.reverse （带或不带！）比办法更快{的Array.sort | X，Y | Y'LT; = GT; X} 。因此，我建议。

array.sort.reverse (with or without !) is way faster than array.sort{|x,y| y<=>x}. Thus, I recommend that.

下面是脚本作为参考：

#!/usr/bin/env ruby
require 'benchmark'

Benchmark.bm do|b|
  master = (1..1_000_000).map(&:to_s).shuffle
  a = master.dup
  b.report("array.sort.reverse      ") do
    a.sort.reverse
  end

  a = master.dup
  b.report("array.sort.reverse!     ") do
    a.sort.reverse!
  end

  a = master.dup
  b.report("array.sort!.reverse!    ") do
    a.sort!.reverse!
  end

  a = master.dup
  b.report("array.sort{|x,y| y<=>x} ") do
    a.sort{|x,y| y<=>x}
  end
end

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