From: Chris Shea <cmshea@...>
Date: 2007-02-02T15:20:08+09:00
Subject: Re: halving a string

On Feb 1, 11:03 pm, Devin Mullins <twif...@comcast.net> wrote:
> Naive solution:
>
> class String
>    def halve(max_len=nil)
>      raise if max_len and size > max_len * 2 + 1
>      space_indices = (0...size).find_all {|i| self[i] == ' '[0] }
>      splitter = space_indices.sort_by {|i| (i - size/2).abs }.first
>      if splitter.nil? ||
>        (max_len && (splitter > max_len || size - splitter - 1 > max_len))
>        [self[0...size/2], self[size/2..-1]]
>      else
>        [self[0...splitter], self[splitter+1..-1]]
>      end
>    end
> end
>
> if __FILE__ == $0
>    require 'test/unit'
>
>    class SplitterTest < Test::Unit::TestCase
>      def test_stuff
>        assert_equal ['the frog', 'is green'], 'the frog is green'.halve
>        assert_equal ['ponchielli', 'wrote songs'],
>                     'ponchielli wrote songs'.halve
>        assert_raise(RuntimeError) { 'ab d'.halve 1 }
>        assert_nothing_raised { 'a b'.halve 1 }
>        assert_equal ['lizardman', 'lives'], 'lizardman lives'.halve
>        assert_equal ['lizardm', 'an lives'], 'lizardman lives'.halve(8)
>        assert_equal ['abcdef','ghijkl'], 'abcdefghijkl'.halve
>      end
>    end
> end

Yes. I see how expressions like space_indices.sort_by {|i| (i - size/
2).abs }.first work, I just need to be able to think of them. It does
what I really want (get the closest space to the middle of the
string), instead of what I almost want (the last space in the first
half of the string). Maybe I just gave up too early, or started
barking up the wrong tree. I said, "I know, I'll use regular
expressions" and then I had two problems. Thanks.