From: Adam Prescott <mentionuse@...>
Date: 2011-03-10T08:42:18+09:00
Subject: Re: [Code] Touch Typing Tutor What do you think of my code?

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On Wed, Mar 9, 2011 at 11:27 PM, JP Billaud <jp.billaud@gmail.com> wrote:

> class String
>  def compare_sum_errors other
>    cnt = [self.length, other.length].min
>
>    (0..(cnt-1)).inject(0) do |errors, idx|
>      next errors + 1 if self[idx] != other[idx]
>      errors
>    end + (self.length - other.length).abs
>  end
> end
>
> str1 = "test origin string"
> str2 = "test diff string"
>
> puts str1.compare_sum_errors str2
>

This isn't the best use of inject. :)

This is much more readable, I find:

def count_errors(first, second)
  # reorder things so that first is always <= second
  first, second = [first, second].sort_by { |s| s.length }

  errors = 0

  first.chars.zip(second.chars).each do |f, s|
    errors += 1 if f != s
  end

  # over-typing is an error
  errors + (second.length - first.length)
end

count_errors("hello", "helloo") #=> 0
count_errors("hello", "helllo") #=> 2

str1 = "test origin string"
str2 = "test diff string"
count_errors(str1, str2) #=> 13 (same result as the inject)

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