Re: move all 0s in an array to the beginning keeping other elements order same

One more variation on sort:

use strict;
use warnings;
my @array = (3, 5, 0, 0, 7, 7, 0, 8, 2, 0, 1, 8, 4);
my @sorted_array = sort {($a xor $b) ? ($a <=> $b) : 0 } @array;
print "@sorted_array\n";
[download]

Bill

Comment on Re: move all 0s in an array to the beginning keeping other elements order same Download Code

Replies are listed 'Best First'.
Re^2: move all 0s in an array to the beginning keeping other elements order same by ikegami (Patriarch) on May 02, 2014 at 17:07 UTC
Add `use sort 'stable';` to ensure you get the correct result.	[reply] [d/l]
Re^3: move all 0s in an array to the beginning keeping other elements order same by Laurent_R (Canon) on May 04, 2014 at 11:39 UTC
Hi ikegami, can you please explain why using the `use sort 'stable';` pragma would be important? Admittedly, the sorting block is peculiar and treats non 0 values as equal so that non 0 values may be reshuffled in the process (as would be the case using quick sort). However, since Perl 5.8, the default sorting algorithm (merge sort) is inherently stable, so I would expect the order of non 0 values to be preserved. Is there anything that I am missing?	[reply] [d/l]
Re^4: move all 0s in an array to the beginning keeping other elements order same by davido (Cardinal) on May 05, 2014 at 04:36 UTC
Possibly the fact that sort internally uses a stable merge sort is an implementation detail, not a semantic guarantee. Specifying stable explicitly means that if the luck of implementation changes the semantics will still remain in tact. Dave	[reply]
Re^5: move all 0s in an array to the beginning keeping other elements order same by Laurent_R (Canon) on May 05, 2014 at 06:09 UTC
Re^6: move all 0s in an array to the beginning keeping other elements order same by davido (Cardinal) on May 05, 2014 at 06:35 UTC
Re^6: move all 0s in an array to the beginning keeping other elements order same by ikegami (Patriarch) on May 31, 2014 at 04:58 UTC
Some notes below your chosen depth have not been shown here
Re^3: move all 0s in an array to the beginning keeping other elements order same by BillKSmith (Monsignor) on May 02, 2014 at 21:36 UTC
Thanks, I forgot about stability, especially when my single test case workeed correctly. Bill	[reply]


laziness, impatience, and hubris
	PerlMonks