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Re^3: Finding an intersection of two sets, lean and mean

by Sinister (Friar)
on Jun 29, 2005 at 14:52 UTC ( #471044=note: print w/replies, xml ) Need Help??

in reply to Re^2: Finding an intersection of two sets, lean and mean
in thread Finding an intersection of two sets, lean and mean

Found it!

Perhaps you meant 'grep' instead of 'map' ?? ;->

This gives a different result set then mine (larger in every case), but this could be a problem with my code...

It is faster, untill the sets become a teeny weeny bit bigger (eg: +5M lines)
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Re^4: Finding an intersection of two sets, lean and mean
by dragonchild (Archbishop) on Jun 29, 2005 at 15:00 UTC
    Yes, grep is the correct operator, not map. See - I did bork my code. :-)

    As for the +5M lines thing - that becomes a function of your available RAM. Your string solution will hit the same limit, but at around 20-30M (if 5M is your limit with hashes).

    Note, your code to build the hash string will bomb faster than your code to iterate through it because you use foreach instead of while to iterate through the list. This creates a copy of the list you're foreach'ing through whereas while does not.

    My criteria for good software:
    1. Does it work?
    2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

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