Re^4: sorting by numbers then alphabetically

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Re^5: sorting by numbers then alphabetically by Anonymous Monk on Dec 23, 2010 at 18:23 UTC
how would i do this by passing an array reference and not the array. can you call sort on an array ref?	[reply]
Re^6: sorting by numbers then alphabetically by Marshall (Canon) on Dec 23, 2010 at 18:31 UTC
You need to send a list of things into the sort function. If you have a ref to an array, just de-reference that to get the the list of stuff. `@$aref = sort @$aref;` [download] Update: The way that a Schwartzian transform works more efficiently is that it pre-computes this stuff like: `my $a_region = lc ($a->region_name);` so that it doesn't have be redone again and again for each pair of things to be compared. The Perl sort algorithm changes from release to release. Version 5.10 which I use now, uses merge sort instead of quick sort. In my benchmarking it is, in general, faster, much faster than previous versions. The net of this is that techniques like the Schwartzian transform don't bring as big a percentage decrease in sort time because there are fewer comparisons being done. As a beginner, I would recommend keeping things simple. Don't knock yourself out to gain a 10-15% reduction in something that is usually so fast anyway that it doesn't matter. That's why I offered my sort solution. Do not confuse brevity with execution efficiency and certainly not clarity! The "if" part of my code will run very quickly and could also be combined into a Schwartzian transform solution (the key part is the pre-computation of say lc($a).	[reply] [d/l] [select]
Re^6: sorting by numbers then alphabetically by Tux (Canon) on Dec 23, 2010 at 21:13 UTC
`my $newref = [ map { $_->[0] } sort { $a->[1] <=> $b->[1] \|\| $a->[2] cmp $b->[2] } map { my $s = $_->seq_region_name; [ $_, $s =~ m/^[0-9]+$/ ? $s : 999, lc $s ] } @$oldref ];` [download] Enjoy, Have FUN! H.Merijn	[reply] [d/l]