From: "Peña, Botp" <botp@...>
Date: 2008-04-15T11:08:29+09:00
Subject: Re: noob 'why doesn't this work' question

From: list-bounce@example.com 
# And thanks to everyone who responded. 101 ways to do this would
# be great, but I'll settle for 4 or 5. ;-)

i hope this catches up the 5th way :)

ruby1.9 though,

irb(main):004:0> sizeList.group_by.with_index{|e,i| countarray.include? i}
=> {false=>[0, 1, 2, 5], true=>[3, 4, 6]}

fr here you can get what gets deleted,

irb(main):016:0> sizeList.group_by.with_index{|e,i| countarray.include? i}[true]
=> [3, 4, 6]

and what remains,

irb(main):017:0> sizeList.group_by.with_index{|e,i| countarray.include? i}[false]
=> [0, 1, 2, 5]

the beauty here is you can go slowly, and picture out and compare in advance what will be deleted and what will remain...

kind regards -botp