Re: Sort by -M

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1208341

use strict;
use warnings;
use Data::Dump 'pp';

my @tmparray = (<d.tree*>, 'nosuchfile'); # for testing purposes...
pp \@tmparray;

# replace
# @tmparray = sort { -M "$b" <=> -M "$a" } (@tmparray);
# with
@tmparray =
  map $_->[0],
  sort { $b->[1] <=> $a->[1] }
  grep defined $_->[1],
  map [ $_, -M $_ ],
  @tmparray;
# end replace

pp \@tmparray;
[download]

Comment on Re: Sort by -M Download Code

Replies are listed 'Best First'.
Re^2: Sort by -M by roperl (Beadle) on Feb 02, 2018 at 20:33 UTC
That looks like it'll work. Can you explain it. I'm not familiar with map	[reply]
Re^3: Sort by -M by AnomalousMonk (Archbishop) on Feb 02, 2018 at 23:08 UTC
See map and some of the articles in the List Processing, Filtering, and Sorting section of the Monastery Tutorials, perhaps esp. Map: The Basics and Understanding transformation sorts (ST, GRT), the details. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l]
Re^3: Sort by -M by Marshall (Canon) on Feb 03, 2018 at 09:55 UTC
map is a special "short-hand" for a "foreach loop". All map statements can be expressed as a "foreach loop". Consider: `#!/usr/bin/perl use strict; use warnings; my @array = (1,2,3); @array = map {$_+1}@array; print "@array\n"; #prints: 2 3 4 foreach my $num (@array) { $num++; } print "@array\n"; #prints: 3 4 5` [download] Update: As an additional comment, sometimes I see a comment like "I didn't want to use a loop, so I used map". That is wrong. Map is a looping instruction whether it looks that way in the source code or not. A map vs a foreach loop winds up being basically the same in terms of how the input array is processed. I've seen 1/2 page map statements which in my opinion is an abuse of the feature. I use map for simple one line transformation operations. Mileage and situations vary.	[reply] [d/l]