Hey Rob,
Just got a very simple version to work. Based on your code
def self.split_when(*value)
results = [[]]
each do |element|
results.last << element
if value.include?(element)
results << []
end
end
results
end
So, again, A = [h1, h2, h3, h4, h5, ..., hn]
and some for some hi, hi[:cue] = true.
I then run
A.split_when({:cue=>true})
to get
[[h1,h2,h3], [h4, h5], ... , [hj,...,hn] ]
Thanks again for the detailed code!
On Aug 7, 12:14 pm, Rob Biedenharn <[email protected]>
wrote:
> On Aug 7, 2009, at 11:05 AM, Nik wrote:
>
> > Thanks Rob, in line 6 (where #!/usr/bin/ruby -w is line 1) where
> > results[-1]<<element, is there a check to verify that the element's
> > cue is true and henceforth start a new and empty array?
>
> No, but lines 7..9 do and line 11 discards the empty array when the
> last element was a cutoff (element[:cue] in this case) and was not
> needed to hold other elements.
>
> -Rob
>
>
>
> > On Aug 6, 6:32 pm, Rob Biedenharn <[email protected]> wrote:
> >> On Aug 6, 2009, at 3:22 PM, Nik wrote:
>
> >>> Hello, I have this big array of hashes:
> >>> A =[ h0, h1, h2, ..., hn]
> >>> some hi's' :cue key is true, others' is false.
> >>> e.g.,
> >>> h1[:cue] = false
> >>> h2[:cue] = false
> >>> h3[:cue] = true
> >>> h4[:cue] = false
> >>> h5[:cue] = true
> >>> ...
> >>> hn[:cue] = ...
>
> >>> Again, these hashes are in an array, A.
>
> >>> Now, I'd like to group them into smaller arrays whose last item
> >>> has a
> >>> true cue
> >>> so
> >>> A' = [ [h1, h2, h3], [h4, h5], ... , [...] ]
>
> >>> Is there a built-in method to cook this up?
> >>> If not, what combination of methods might you think would work most
> >>> efficiently?
>
> >>> Thank You
>
> >> Well, this seems to be a tasty dish. I took some liberty with your
> >> minimal spec, but you should see the first test for the usage that
> >> maps to your example.
>
> >> #!/usr/bin/ruby -w
> >> class Array
> >> def split_when
> >> result = [[]]
> >> each do |element|
> >> result[-1] << element
> >> if block_given? ? yield(element) : element
> >> result << []
> >> end
> >> end
> >> result.pop if result.last.empty?
> >> result
> >> end
> >> end
>
> >> if File.expand_path($0) == File.expand_path(__FILE__)
> >> require 'test/unit'
> >> class SplitWhenTest < Test::Unit::TestCase
> >> def setup
> >> h1 = { :cue => false }
> >> h2 = { :cue => false }
> >> h3 = { :cue => true }
> >> h4 = { :cue => false }
> >> h5 = { :cue => true }
> >> �...@ary = [ h1, h2, h3, h4, h5 ]
> >> �...@expected = [ [h1, h2, h3], [h4, h5] ]
> >> end
>
> >> def test_example_from_email
> >> assert_equal @expected, @ary.split_when {|e| e[:cue]}
> >> end
>
> >> def test_simple
> >> original = [ false, true, false, false, true, true, false,
> >> true, false, true, false ]
> >> expected = [[false, true],[false, false, true],[true],[false,
> >> true],[false, true],[false]]
> >> assert_equal expected, original.split_when, "no block"
> >> assert_equal expected, original.split_when {|e|e}, "simple
> >> block"
> >> end
> >> end
> >> end
> >> __END__
>
> >> :code/ruby $ ./array_split_when.rb
> >> Loaded suite ./array_split_when
> >> Started
> >> ..
> >> Finished in 0.000585 seconds.
>
> >> 2 tests, 3 assertions, 0 failures, 0 errors
>
> >> -Rob
>
> Rob Biedenharn http://agileconsultingllc.com
> [email protected]
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