假设我有
ary = ['aa', 'b', 'cba', 'd', 'df']
并想找到所有匹配的元素的索引/a/。很容易得到相关的值，使用
ary.find_all { |v| v =~ /a/ }
=> ["aa", "cba"]
我想写的是
ary.find_all_indices { |v| v =~ /a/ }
但没有这样的事情。我能想到的只有
(0..ary.size-1).find_all { |i| ary[i] =~ /a/ }
=> [0, 2]
谁能帮我找到更好的东西？
没有find_all_indices，但你可以自由组合each_index和find_all：
ary.each_index.find_all{|i| ary[i] =~ /a/}
# => [0, 2]
总是有兴趣看看什么跑得最快：
require 'benchmark'
N = 10_000
ARY = ('aa' .. 'zz').to_a
DIVIDER = '-' * 40
def sergio_tulentsev(ary)
ary.each.with_index.select { |v, idx| v =~ /a/ }.map{|v, i| i}
end
def priti(ary)
(0..ary.size - 1).each_with_object([]) { |v,ob| ob << v if ary[v].include? 'a'}
end
def darshan_computing(ary)
ary.each_index.find_all{|i| ary[i] =~ /a/}
end
puts "Ruby version: #{`ruby -v`}"
puts DIVIDER
puts 'Sergio Tulentsev: ' + sergio_tulentsev(ARY).join(',')
puts 'Priti: ' + priti(ARY).join(',')
puts 'Darshan Computing: ' + darshan_computing(ARY).join(',')
puts DIVIDER
2.times do
Benchmark.bm(17) do |b|
b.report('Sergio Tulentsev') { N.times { sergio_tulentsev(ARY) }}
b.report('Priti') { N.times { priti(ARY) }}
b.report('Darshan Computing') { N.times { darshan_computing(ARY) }}
end
end
哪个输出：
Ruby 版本：ruby 1.9.3p392（2013-02-22 修订版 39386）[x86_64-darwin10.8.0]
----------------------------------------
Sergio Tulentsev: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Darshan Computing: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Sergio Tulentsev 4.270000 0.000000 4.270000 ( 4.272826)
Priti 2.020000 0.010000 2.030000 ( 2.025979)
Darshan Computing 3.690000 0.010000 3.700000 ( 3.704790)
user system total real
Sergio Tulentsev 4.240000 0.010000 4.250000 ( 4.239833)
Priti 2.000000 0.000000 2.000000 ( 2.001301)
Darshan Computing 3.700000 0.020000 3.720000 ( 3.718807)
Ruby 版本：ruby 1.9.3p429（2013-05-15 修订版 40747）[x86_64-darwin10.8.0]
----------------------------------------
Sergio Tulentsev: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Darshan Computing: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Sergio Tulentsev 4.520000 0.010000 4.530000 ( 4.529948)
Priti 2.150000 0.000000 2.150000 ( 2.153721)
Darshan Computing 3.370000 0.010000 3.380000 ( 3.390537)
user system total real
Sergio Tulentsev 4.560000 0.010000 4.570000 ( 4.580625)
Priti 2.230000 0.010000 2.240000 ( 2.228714)
Darshan Computing 3.560000 0.000000 3.560000 ( 3.567562)
Ruby 版本：ruby 2.0.0p0（2013-02-24 修订版 39474）[x86_64-darwin10.8.0]
----------------------------------------
Sergio Tulentsev: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Darshan Computing: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Sergio Tulentsev 13.770000 0.020000 13.790000 ( 13.801769)
Priti 7.760000 0.010000 7.770000 ( 7.774238)
Darshan Computing 8.720000 0.020000 8.740000 ( 8.743842)
user system total real
Sergio Tulentsev 12.930000 0.010000 12.940000 ( 12.948077)
Priti 7.890000 0.010000 7.900000 ( 7.898609)
Darshan Computing 8.450000 0.010000 8.460000 ( 8.464012)
这些值让我感到惊讶，所以我在不同的时间运行了两次，它们是一致的。
Ruby 版本：ruby 2.0.0p195（2013-05-14 修订版 40734）[x86_64-darwin10.8.0]
----------------------------------------
Sergio Tulentsev: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Darshan Computing: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Sergio Tulentsev 4.890000 0.010000 4.900000 ( 4.899299)
Priti 2.110000 0.000000 2.110000 ( 2.115395)
Darshan Computing 3.710000 0.010000 3.720000 ( 3.727729)
user system total real
Sergio Tulentsev 4.960000 0.020000 4.980000 ( 4.971293)
Priti 2.170000 0.000000 2.170000 ( 2.182052)
Darshan Computing 3.620000 0.010000 3.630000 ( 3.623773)
我的机器现在正忙于运行其他东西，所以这些值可能比别人的机器慢一点，尤其是较新的机器，但重要的是相对值。
Ruby v2.0-p0 显示的结果要慢得多。不知道为什么。这是结果，我编写的算法可以减少时间。我认为 Priti 的代码总体上是最好的，尽管我认为它可能会被扭曲并加快速度。
def tinman2(ary)
idxes = []
ary.size.times { |idx| (idxes << idx) if (ary[idx] =~ /a/) }
idxes
end
Ruby version: ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-darwin10.8.0]
----------------------------------------
Sergio Tulentsev: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Darshan Computing: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman2: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Sergio Tulentsev 11.600000 0.050000 11.650000 ( 11.646425)
Priti 6.880000 0.020000 6.900000 ( 6.903026)
Darshan Computing 7.560000 0.000000 7.560000 ( 7.562145)
TheTinMan2 6.690000 0.000000 6.690000 ( 6.695731)
user system total real
Sergio Tulentsev 11.590000 0.010000 11.600000 ( 11.593051)
Priti 6.880000 0.000000 6.880000 ( 6.889174)
Darshan Computing 7.580000 0.000000 7.580000 ( 7.573390)
TheTinMan2 6.600000 0.000000 6.600000 ( 6.607929)
user system total real
Sergio Tulentsev 11.580000 0.010000 11.590000 ( 11.582659)
Priti 6.880000 0.000000 6.880000 ( 6.878172)
Darshan Computing 7.590000 0.000000 7.590000 ( 7.591342)
TheTinMan2 6.590000 0.000000 6.590000 ( 6.598353)
Borodin 要求添加他的算法。我也添加了另一个使用include。
def tinman6(ary)
idxes = []
ary.size.times { |idx| (idxes << idx) if (ary[idx].include?('a')) }
idxes
end
def borodin(ary)
ary.each_index.find_all { |i| ary[i].include? 'a' }
end
Ruby 版本：ruby 1.9.3p392（2013-02-22 修订版 39386）[x86_64-darwin10.8.0]
----------------------------------------
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman2: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman6: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Borodin: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Priti 1.880000 0.000000 1.880000 ( 1.874891)
TheTinMan2 3.330000 0.000000 3.330000 ( 3.337149)
TheTinMan6 1.660000 0.000000 1.660000 ( 1.658698)
Borodin 1.740000 0.000000 1.740000 ( 1.738520)
user system total real
Priti 1.870000 0.000000 1.870000 ( 1.872923)
TheTinMan2 3.320000 0.000000 3.320000 ( 3.314796)
TheTinMan6 1.650000 0.000000 1.650000 ( 1.650655)
Borodin 1.730000 0.000000 1.730000 ( 1.732083)
user system total real
Priti 1.870000 0.000000 1.870000 ( 1.871353)
TheTinMan2 3.330000 0.000000 3.330000 ( 3.332134)
TheTinMan6 1.650000 0.000000 1.650000 ( 1.651290)
Borodin 1.730000 0.000000 1.730000 ( 1.731993)
Ruby 版本：ruby 1.9.3p429（2013-05-15 修订版 40747）[x86_64-darwin10.8.0]
----------------------------------------
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman2: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman6: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Borodin: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Priti 1.840000 0.000000 1.840000 ( 1.833698)
TheTinMan2 3.090000 0.000000 3.090000 ( 3.095056)
TheTinMan6 1.680000 0.000000 1.680000 ( 1.676831)
Borodin 1.760000 0.000000 1.760000 ( 1.766091)
user system total real
Priti 1.840000 0.000000 1.840000 ( 1.834253)
TheTinMan2 3.100000 0.000000 3.100000 ( 3.102027)
TheTinMan6 1.720000 0.000000 1.720000 ( 1.726131)
Borodin 1.780000 0.000000 1.780000 ( 1.772062)
user system total real
Priti 1.830000 0.000000 1.830000 ( 1.833505)
TheTinMan2 3.110000 0.000000 3.110000 ( 3.107236)
TheTinMan6 1.670000 0.000000 1.670000 ( 1.677120)
Borodin 1.770000 0.000000 1.770000 ( 1.763458)
Ruby 版本：ruby 2.0.0p0（2013-02-24 修订版 39474）[x86_64-darwin10.8.0]
----------------------------------------
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman2: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman6: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Borodin: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Priti 6.860000 0.030000 6.890000 ( 6.891947)
TheTinMan2 6.680000 0.030000 6.710000 ( 6.705629)
TheTinMan6 6.170000 0.000000 6.170000 ( 6.175578)
Borodin 7.060000 0.000000 7.060000 ( 7.058933)
user system total real
Priti 6.820000 0.000000 6.820000 ( 6.828020)
TheTinMan2 6.600000 0.000000 6.600000 ( 6.600167)
TheTinMan6 6.050000 0.010000 6.060000 ( 6.046283)
Borodin 6.870000 0.000000 6.870000 ( 6.868911)
user system total real
Priti 6.840000 0.000000 6.840000 ( 6.847487)
TheTinMan2 6.600000 0.000000 6.600000 ( 6.599859)
TheTinMan6 6.060000 0.000000 6.060000 ( 6.058301)
Borodin 6.880000 0.000000 6.880000 ( 6.886744)
Ruby 版本：ruby 2.0.0p195（2013-05-14 修订版 40734）[x86_64-darwin10.8.0]
----------------------------------------
Priti: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman2: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Tinman6: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
Borodin: 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,52,78,104,130,156,182,208,234,260,286,312,338,364,390,416,442,468,494,520,546,572,598,624,650
----------------------------------------
user system total real
Priti 1.900000 0.010000 1.910000 ( 1.908870)
TheTinMan2 3.330000 0.020000 3.350000 ( 3.353368)
TheTinMan6 1.800000 0.000000 1.800000 ( 1.807138)
Borodin 1.780000 0.010000 1.790000 ( 1.786934)
user system total real
Priti 1.890000 0.010000 1.900000 ( 1.896419)
TheTinMan2 3.320000 0.010000 3.330000 ( 3.331743)
TheTinMan6 1.810000 0.010000 1.820000 ( 1.821966)
Borodin 1.790000 0.000000 1.790000 ( 1.784046)
user system total real
Priti 1.880000 0.000000 1.880000 ( 1.884283)
TheTinMan2 3.330000 0.000000 3.330000 ( 3.332970)
TheTinMan6 1.810000 0.000000 1.810000 ( 1.812595)
Borodin 1.780000 0.010000 1.790000 ( 1.782502)
ary = ['aa', 'b', 'cba', 'd', 'df']
(0..ary.size - 1).each_with_object([]) { |v,ob| ob << v if ary[v].include? 'a'}
# => [0, 2]
这也是一个简单的解决方案。
不打扰地图，因为这是通过块中索引的集合完成的。另外，使用地图，无论如何我都必须删除nil条目，也许使用uniq然后忽略一次出现nil
indices = []
%w[here there are not many words with an a in them].each_with_index {|word, i| indices << i if word =~ /a/}
希望能帮助到你。