refactoring request

[Bil Kleb]

Hi,

I've stalled out on making this simpler, and I'm
seeking help pairing this beast down...

Given unused is a hash of arrays where each array has
repeated elements, make elements unique in each array and
remove all names that are not repeated MagicNumber times.
Finally, remove any hash pairs that hold an empty array.

unused.each do |source,routines|
orphans = routines.uniq
orphans.delete_if do |orphan|
repeated = routines.find_all{ |routine| routine == orphan }.size
repeated != MagicNumber
end
unused[source] = orphans
end
unused.delete_if{ |h,k| k.empty? }

Thanks,

 

[James Gray]

Given unused is a hash of arrays where each array has
repeated elements, make elements unique in each array and
remove all names that are not repeated MagicNumber times.
Finally, remove any hash pairs that hold an empty array.

unused.each do |source,routines|
orphans = routines.uniq
orphans.delete_if do |orphan|
repeated = routines.find_all{ |routine| routine == orphan }.size
repeated != MagicNumber
end
unused[source] = orphans
end
unused.delete_if{ |h,k| k.empty? }

unused = unused.inject(Hash.new) |result, (source, routines)|
orphans = routines.uniq.reject do |o|
routines.inject(0) { |c, r| c + (r == o ? 1 : 0) } != MagicNumber
end
orphans.empty? ? result : result.merge(source => orphans)
end

Hmm, I'm not really sure I did much better there.

James Edward Gray II

 

[Robert Dober]

Hi,

I've stalled out on making this simpler, and I'm
seeking help pairing this beast down...

Given unused is a hash of arrays where each array has
repeated elements, make elements unique in each array and
remove all names that are not repeated MagicNumber times.
Finally, remove any hash pairs that hold an empty array.

unused.each do |source,routines|
orphans = routines.uniq
orphans.delete_if do |orphan|
repeated = routines.find_all{ |routine| routine == orphan }.size
repeated != MagicNumber
end
unused[source] = orphans
end
unused.delete_if{ |h,k| k.empty? }

Maybe like this

unused.delete_if{ |source, routines|
routines.delete_if do |o|
routines.inject(0){ |c,r| c + (r == o ? 1 : 0 ) } != MagicNumber
end
routines.uniq!
routines.empty?
}

And I admit freely that the inner inject was stolen from James' try, thanx .
Cheers
Robert

 

[Robert Dober]

unused.delete_if{ |source, routines|
routines.delete_if do |o|

--- routines.inject(0){ |c,r| c + (r == o ? 1 : 0 ) } != MagicNumber
+++ routines.grep(o).size != MagicNumber

 

[James Gray]

--- routines.inject(0){ |c,r| c + (r == o ? 1 : 0 ) } !=
MagicNumber
+++ routines.grep(o).size != MagicNumber

I'm kind of surprised that works. Neat.

However, I think inject() is preferable since it doesn't have to build
up a possibly large Array just to get a count.

James Edward Gray II

 

[Robert Dober]

I'm kind of surprised that works. Neat.

However, I think inject() is preferable since it doesn't have to build
up a possibly large Array just to get a count.

It depends, if space is the issue you are right, if time is an issue
inject is - much to my dispair - not the best idea.
The ideal solution of course is to use Ruby1.9 with count
R.

 

[Robert Dober]

oh sorry I forgot, there is another potential performance problem in
my solution.
... look when I called uniq!.
I went for readability but just wanted to be honest about the
tradeoffs in case this is a problem for Bil.
R.

 

[Bil]

Maybe like this

unused.delete_if{ |source, routines|
routines.delete_if do |r|
routines.grep(r).size != MagicNumber
end
routines.uniq!
routines.empty?
}

Thanks guys!

Again, the replies to my OP via news://comp.lang.ruby
did not come through my newsfeed. Sigh.

Regards,

 

[Robert Klemme]

Hi,

I've stalled out on making this simpler, and I'm
seeking help pairing this beast down...

Given unused is a hash of arrays where each array has
repeated elements, make elements unique in each array and
remove all names that are not repeated MagicNumber times.
Finally, remove any hash pairs that hold an empty array.

unused.each do |source,routines|
orphans = routines.uniq
orphans.delete_if do |orphan|
repeated = routines.find_all{ |routine| routine == orphan }.size
repeated != MagicNumber
end
unused[source] = orphans
end
unused.delete_if{ |h,k| k.empty? }

Here's my solution, untested:

out = unused.inject({}) do |res, (k,v)|
array = v.inject(Hash.new(0)) do |ha, e|
ha[e] += 1
ha
end.inject([]) do |ar,(ke,cn)|
ar << ke if cn == MagicNumber
ar
end
res[k] = array unless array.empty?
res
end

Kind regards

robert

 

[Gary Wright]

unused.each do |source,routines|
orphans = routines.uniq
orphans.delete_if do |orphan|
repeated = routines.find_all{ |routine| routine == orphan }.size
repeated != MagicNumber
end
unused[source] = orphans
end
unused.delete_if{ |h,k| k.empty? }

Here is my attempt. It uses Symbol#to_proc.

module Enumerable
def frequency
inject(Hash.new(0)) { |r, e| r[e] += 1; r }
end
end

def clense(data, magic)
data.inject({}) { |r, (src, rlist)|
l = rlist.frequency.select { |r, c| c == magic }.map(&:first)
r[src] = l unless l.empty?
r
}
end

data = {
:gone => [ 0, 1, 2 ],
:dups => [ 0, 0, 1, 1, 2, 2],
nedups => [ 0, 1, 1, 2, 2, 2],
:threes => [ 0, 0, 0, 1, 1, 1, 2,2,2]
}

p clense(data, 2)