Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

Re: removing the goto

by kwaping (Priest)
on Jun 01, 2007 at 17:23 UTC ( #618804=note: print w/ replies, xml ) Need Help??


in reply to removing the goto

I had the benefit of a direct discussion with the OP about this, which brought much clarity as to his intentions. He has an array of ~4000 elements and wants to select five non-duplicates out of there. So basically, his code can be reduced to this:

use List::Util 'shuffle'; my %unique = map { $_ => 1 } @weighteddiv; my @shuffled = shuffle(keys %unique); @selected = @shuffled[0..4];
I noticed he was randomizing the array, then selecting random indices from there, which was not only reduntdant but created the issue of potentially selecting the same element.

Update: The big array is *not* already internally unique after all, so I had to add the line to unique it.

Update 2: My solution is no longer relevant, after the OP updated with more information. However, I'm leaving my code as-is because it might help a future monk looking for a similar solution.

---
It's all fine and dandy until someone has to look at the code.


Comment on Re: removing the goto
Download Code
Re^2: removing the goto
by jdporter (Canon) on Jun 01, 2007 at 18:27 UTC
    use List::Util 'shuffle'; use List::MoreUtils 'uniq'; my @shuffled = shuffle( uniq @weighteddiv ); @selected = @shuffled[0..4];
      It might be more appropriate to do the shuffle before the uniq if the OP wants the duplicate values to have a greater chance of being selected - as suggested by the name @weighteddiv.
      use List::Util 'shuffle'; use List::MoreUtils 'uniq'; use strict; my @weighteddiv = ( (1..50), (1..10) x 10, ); my @shuffle1 = shuffle( uniq @weighteddiv ); my @shuffle2 = uniq( shuffle @weighteddiv ); printf "shuffle1: %s\n", join(', ', sort {$a <=> $b} @shuffle1[0..10]) +; printf "shuffle2: %s\n", join(', ', sort {$a <=> $b} @shuffle2[0..10]) +;
      Output:
      shuffle1: 2, 5, 16, 17, 23, 25, 26, 27, 39, 42, 43 shuffle2: 1, 3, 4, 5, 6, 8, 9, 10, 13, 40, 50
      This approach is appropriate for the current implementation of uniq, which preserves the original order while removing duplicates.

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://618804]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others wandering the Monastery: (9)
As of 2015-07-03 12:57 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









    Results (53 votes), past polls