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Re: Re: Trying to get fancy...

by Purdy (Hermit)
on Nov 28, 2001 at 20:36 UTC ( #128089=note: print w/replies, xml ) Need Help??


in reply to Re: Trying to get fancy...
in thread Trying to get fancy...

Yep - for each element in @listB, I want to pry out the first element, assign it to $b and then do another nested grep on all elements of @listA and see if $b is in there. If it isn't, then I want it assigned to the overall @listToExpire array.

I rewrote the line to use the { }'s:

@listToExpire = grep { $b = (@{$_})[0] && grep { $a = (@{$_})[0] && $b != $a } @listA } @listB;

Still the same result:
Use of uninitialized value in numeric ne (!=) at ./listMgr.pl line 62.
Use of uninitialized value in numeric ne (!=) at ./listMgr.pl line 62.

I know I could do it in a more readable foreach loop (or a lookup hash), but thought I would take on a challenge, instead. :)

Jason

Update: I got it to work! Thanks, dragonchild! Here's the final version:

@listToExpire = grep { $b = (@{$_})[0]; grep { $a = (@{$_})[0]; $b != +$a } @listA } @listB;

It was those '&&''s ... I still don't understand them outside of the typical boolean EXPR. Need to grok that & the 'and|or' stuff, too.

Replies are listed 'Best First'.
Re: Re: Re: Trying to get fancy...
by AidanLee (Chaplain) on Nov 28, 2001 at 20:45 UTC

    Though readability may not be a high priority for you in this excercise, consider changing this:

    (@{$_})[0]

    to this

     $_->[0]
      *laugh* ... thanks. Lord help whomever adopts my code whenever that happens. Fortunately, this exercise is for a temporary utility script, but with my success, I will prolly adopt it more often. Hermmmm...

      Jason

      If I could have voted this up twice, I would have. :)

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