From: Felix Windt <fwmailinglists@...>
Date: 2007-10-16T02:59:57+09:00
Subject: Re: big array, problems with deleting all empty items

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> -----Original Message-----
> From: Simon Schuster [mailto:significants@gmail.com] 
> Sent: Monday, October 15, 2007 10:42 AM
> To: ruby-talk ML
> Subject: big array, problems with deleting all empty items
> 
> it seems that I have to run it a couple different times for it to
> work.. array.length = 16576, if that could be a potential problem. if
> it is, how do I work around it?
> 
> 077:0> array = File.read("/text.txt").to_a.each { |x| x.chomp! }
> 080:0> array.each_with_index { |x,y|
>     array.delete_at(y) if x.empty? == true
> }
> 
> still leaves me with plenty of empty array items
> 080:0> array[-3]
> ""
> 

I think that might be due to the fact that you're removing elements from an
array that is still being iterated on.
If element 3 is empty, and element 4 is empty, you're deleting element three
in one loop iteration. At that moment, former element 4 now becomes element
3. Your iteration jumps to element 4, effectively skipping that empty
element, never checking it.

Maybe simply use:
array.delete("") 

To delete all objects in the array that are equal to "".

If you need something more fancy, use:
array.delete_if{|item| block} 

With a block that evaluates to true for every item you want to delete.

HTH,

Felix

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