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I know it's cool to do iterators, but something about derange { print "@_\n" } 1 .. 5; seems more perlish to me...

sub _derange { my( $cb, $todo, @v ) = @_; @$todo or return $cb->( @v ); my %seen; @seen{@v}=(); my( $range, @todo ) = @$todo; _derange( $cb, \@todo, @v, $_ ) for grep { ! exists $seen{$_} } @$range; } sub derange(&@) { my $cb = shift; _derange( $cb, [ map { my $x = $_; [ grep { $_ ne $x } @_ ] } @_ ] ); }


If one needed to allow for deranging a list which contains duplicates, one could simply derange the list of its indices. E.g.:

my @x = ( 1 .. 4, 4 ); derange { print "@x[@_]\n" } 0 .. $#x;
We're building the house of the future together.

In reply to Re: Derangements iterator by jdporter
in thread Derangements iterator by tye

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