From: S2 <z@...>
Date: 2008-04-26T23:55:08+09:00
Subject: Re: All occurances of a  character in a string

Raghu Go wrote:

> I did a quick test and like Siep's modifications..
> 
> Method1 Time elapsed: 0.236999988555908 milliseconds
> 
> Siep's modification Method2 Time elapsed: 0.123999834060669 milliseconds
> 

your computer must be really slow :)

s2@magnesium:~/temp$ cat test.rb
def method1(a)
  i = 0
  ret = Hash.new
  a.scan(/./) {|c|
    ret[c] = ret[c].nil? ? [i] : ret[c] << i
    i = i + 1
  }
  p a
  p ret
end

def method2(str) #Siep
  ar = str.split("")
  result = Hash.new{Array.new}

  ar.each_with_index do|item,index|
    result[item] = result[item]<<index
  end
  result.each{|k,v| puts k +  " = " + v.join(",")}
end

def method3(a)
  result = Hash.new{Array.new}
  a.split('').each_with_index {|c, i| result[c] = result[c] << i}
  p result
end
s2@magnesium:~/temp$ irb
irb(main):001:0> require 'benchmark'
=> true
irb(main):002:0> include Benchmark
=> Object
irb(main):003:0> require 'test'
=> true
irb(main):004:0> puts Benchmark.measure {method1("abbccdaab")}
"abbccdaab"
{"a"=>[0, 6, 7], "b"=>[1, 2, 8], "c"=>[3, 4], "d"=>[5]}
  0.000000   0.000000   0.000000 (  0.000227)
=> nil
irb(main):005:0> puts Benchmark.measure {method2("abbccdaab")}
a = 0,6,7
b = 1,2,8
c = 3,4
d = 5
  0.000000   0.000000   0.000000 (  0.000278)
=> nil
irb(main):006:0> puts Benchmark.measure {method3("abbccdaab")}
{"a"=>[0, 6, 7], "b"=>[1, 2, 8], "c"=>[3, 4], "d"=>[5]}
  0.000000   0.000000   0.000000 (  0.000209)
=> nil
irb(main):007:0>