Re: Reverse sort array

A similar approach, but likely slower due to more levels of indirection:

>perl -wMstrict -le
"sub ascending  {   $a cmp $b   }
 sub descending { - ascending() }
 my @ra = qw(q w e r t y u i o p);
 my $sorter = 'descending';
 @ra = sort $sorter @ra;
 print qq{@ra};
 $sorter = 'ascending';
 @ra = sort $sorter @ra;
 print qq{@ra};
"
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e i o p q r t u w y
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Comment on Re: Reverse sort array Download Code

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Re^2: Reverse sort array by johngg (Canon) on Aug 20, 2009 at 13:24 UTC
You can get by with just one sorting routine by reversing the arguments as needed. `$ perl -Mstrict -wle ' > my @arr = qw{ q w e r t y u i o p }; > my $sc = sub { my( $a, $b ) = @_; $a cmp $b }; > my $rev = 0; > my @asc = sort { $rev ? $sc->( $b, $a ) : $sc->( $a, $b) } @arr; > $rev = 1; > my @des = sort { $rev ? $sc->( $b, $a ) : $sc->( $a, $b) } @arr; > print qq{@arr\n@asc\n@des};' q w e r t y u i o p e i o p q r t u w y y w u t r q p o i e $` [download] I hope this is of interest. Cheers, JohnGG	[reply] [d/l]

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Re^2: Reverse sort array
by johngg (Canon) on Aug 20, 2009 at 13:24 UTC

You can get by with just one sorting routine by reversing the arguments as needed.

$ perl -Mstrict -wle '
> my @arr = qw{ q w e r t y u i o p };
> my $sc  = sub { my( $a, $b ) = @_; $a cmp $b };
> my $rev = 0;
> my @asc = sort { $rev ? $sc->( $b, $a ) : $sc->( $a, $b) } @arr;
> $rev    = 1; 
> my @des = sort { $rev ? $sc->( $b, $a ) : $sc->( $a, $b) } @arr;
> print qq{@arr\n@asc\n@des};'
q w e r t y u i o p
e i o p q r t u w y
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$
[download]

I hope this is of interest.

Cheers,

JohnGG

[reply]
[d/l]