Array dynamic intersection and union

ruby-talk
1

Hello,

I was wondering If could intersect and union array dynamic in my code.

Let us say I have these conditions.

array = A & B | (C & D ) & E

Is their any ways of doing these stuff dynamic if all the objects was
arrays.

A = [1,2,3,4,5]

Thanks for any help.

···

--
Posted via http://www.ruby-forum.com/.

2

Why don't you try a few examples and find out? If you still have questions, then at least you can point to actual code to clarify where you need help.

-Rob

Rob Biedenharn
Rob@AgileConsultingLLC.com http://AgileConsultingLLC.com/
rab@GaslightSoftware.com http://GaslightSoftware.com/

···

On Jan 14, 2011, at 4:07 PM, Jamal Soueidan wrote:

Hello,

I was wondering If could intersect and union array dynamic in my code.

Let us say I have these conditions.

array = A & B | (C & D ) & E

Is their any ways of doing these stuff dynamic if all the objects was
arrays.

A = [1,2,3,4,5]

Thanks for any help.

3

Hello Rob,

Sorry I did not explain myself first time.

But I let us say I have these hashes.

rule = {:array => [1,2,3,4], :condition => "AND"}
rule2 = {:array => [1,2,3,4], :condition => "OR"}
rule3 = {:array => [3,4]}

How can I intersection and union based on the conditions in the hash
through them all?

So it end up like this

array = rule[:array] & rule2[:array] | rule3[:array]

···

--
Posted via http://www.ruby-forum.com/.

4

Let me rephrase that because you still aren't giving enough information to really know what you're trying to do.

Given an array of hashes:
input = [ {:array => [1,2,3,4], :condition => "AND"},
           {:array => [2,4,6,8], :condition => "OR"},
           {:array => [1,3]},
         ]
array = input[0][:array] & input[1][:array] | input[2][:array]
=> [2, 4, 1, 3]

Well, if you apply the operations serially, you will actually get something like:

array = ((input[0][:array] & input[1][:array]) | input[2][:array])

Since & is higher precendence than |, the answer is the same, but if you change the order:

array = input[0][:array] | input[1][:array] & input[2][:array]
=> [1, 2, 3, 4]

is not the same as:

array = ((input[0][:array] | input[1][:array]) & input[2][:array])
=> [1, 3]

def combine(arrays)
   result, op = , "OR"
   arrays.each do |hsh|
     case op
     when "OR"
       result |= hsh[:array]
     when "AND"
       result &= hsh[:array]
     end
     op = hsh[:condition]
   end
   result
end

combine(input)
#=> [2, 4, 1, 3]

-Rob

Rob Biedenharn
Rob@AgileConsultingLLC.com http://AgileConsultingLLC.com/
rab@GaslightSoftware.com http://GaslightSoftware.com/

···

On Jan 14, 2011, at 5:39 PM, Jamal Soueidan wrote:

Hello Rob,

Sorry I did not explain myself first time.

But I let us say I have these hashes.

rule = {:array => [1,2,3,4], :condition => "AND"}
rule2 = {:array => [1,2,3,4], :condition => "OR"}
rule3 = {:array => [3,4]}

How can I intersection and union based on the conditions in the hash
through them all?

So it end up like this

array = rule[:array] & rule2[:array] | rule3[:array]