Question

  start_time = Time.now
  1000000.times do
        rand(36**1024).to_s(36)
  end
  end_time = Time.now
  puts end_time - start_time

235秒。

有没有更快的方法在ruby中生成随机字符串？

Answer 1

如果您的目标系统有 / dev / urandom ，您可以从中读取随机字节。它应该更快。这是带基准的代码。一些Ruby库使用这种方法生成随机事物。

Benchmark.bm do|b|

    b.report("Ruby #rand  ") do
      100000.times do
        big_key = rand(36**1024).to_s(36)
      end
    end

    b.report("/dev/urandom") do
      File.open("/dev/urandom",File::RDONLY || File::NONBLOCK || File::NOCTTY) do |f|
        100000.times do
          big_key = f.readpartial(512).unpack("H*")[0]
        end
      end
    end
end

在这里你可以看到100000的基准测试结果，1024个字符长的随机字符串......

       user     system      total        real
Ruby #rand   31.750000   0.080000  31.830000 ( 32.909136)
/dev/urandom  0.810000   5.870000   6.680000 (  6.974276)

Answer 2

不需要36**1024 1000000 times

val=36**1024
1000000.times do
  rand(val).to_s(36)
end

这肯定会节省一些时间

Answer 3

您可以随机播放字符串以获取随机字符串

array = rand(36**1024).to_s(36).split(//)

start_time = Time.now
1000000.times do
  array.shuffle.join
end
end_time = Time.now
puts end_time - start_time

＃=＆GT; 126秒

Answer 4

使用securerandom怎么样？

require 'securerandom'

start_time = Time.now
1000000 .times do
  SecureRandom.base64(1024)
end
end_time = Time.now
puts end_time - start_time

Answer 5

1.9.3p194 :113 >   
1.9.3p194 :114 >     start_time = Time.now
 => 2012-10-16 19:51:45 +0530 
1.9.3p194 :115 >   1000000.times do
1.9.3p194 :116 >            (Object.new.hash.to_s << Object.new.hash.to_s)[0..35]
1.9.3p194 :117?>     end
 => 1000000 
1.9.3p194 :118 >   end_time = Time.now
 => 2012-10-16 19:51:46 +0530 
1.9.3p194 :119 >   puts end_time - start_time
1.8252512
 => nil 
1.9.3p194 :120 >

=＆GT; 1.8秒

简而言之Object.new.hash.to_s

有没有更快的方法在ruby中生成随机字符串？

5 个答案: