Ruby String类中是否有任何内置函数可以为我提供Ruby中字符串的所有前缀.就像是：
"ruby".all_prefixes => ["ruby","rub","ru","r"]
def all_prefixes search_string
dup_string = search_string.dup
return_list = []
while(dup_string.length != 0)
return_list << dup_string.dup
dup_string.chop!
end
return_list
end
但我正在寻找更多的rubylike,更少的代码和神奇的东西.
注意：当然不用说original_string应保持不变.
解决方法
快速基准：
require 'fruity'
string = 'ruby'
compare do
toro2k do
string.size.times.collect { |i| string[0..i] }
end
marek_lipka do
(0...(string.length)).map{ |i| string[0..i] }
end
jorg_w_mittag do
string.chars.inject([[],'']) { |(res,memo),c|
[res << memo += c,memo]
}.first
end
jorg_w_mittag_2 do
acc = ''
string.chars.map {|c| acc += c }
end
stefan do
Array.new(string.size) { |i| string[0..i] }
end
end
最终获胜者是：
Running each test 512 times. Test will take about 1 second. jorg_w_mittag_2 is faster than stefan by 19.999999999999996% ± 10.0% stefan is faster than marek_lipka by 10.000000000000009% ± 10.0% marek_lipka is faster than jorg_w_mittag by 10.000000000000009% ± 1.0% jorg_w_mittag is similar to toro2k