function that returns the middle of an array
This function returns the middle of a array sorted array
sub Return_Middle
{
my @list = @_;
return @list if ( scalar(@list) == 2 or
scalar(@list) == 1 );
my @sorted = sort { $a <=> $b || $a cmp $b } @list;
my @middle = drill_down(@sorted);
return @middle;
sub drill_down
{
my @list = @_;
return @list if ( scalar(@list) == 2 );
return @list if ( scalar(@list) == 1 );
splice @list, -1, 1;
splice @list, 0, 1;
drill_down(@list);
}
}
Re: function that returns the middle of an array
created: 2006-01-10 09:26:44
How 'bout
sub drill_down {
my $i=@_/2;
@_[ @_%2 ? $i : ($i-1, $i) ];
}
instead?
Also, in various order:
- No need for those [doc://scalar]s as == will impose scalar context anyway,
- You may just do:
drill_down(@sorted); # as the last statement in your sub
instead ofmy @middle = drill_down(@sorted); return @middle;
- While it is perfectly legal to define the drill_down sub inside the Return_Middle one, they will be "global" anyway, and to do so would have some sense only if the former were a closure around some variable(s) lexically scoped to the latter, which is not the case.
Re: function that returns the middle of an array
created: 2006-01-10 10:57:59
How about this? You find the middle of the array, which will either be an integer or a half-value. Return the slice indexed from the integer portion of the midpoint through the integer portion of the midpoint + .5. If the midpoint is a half-value, those will be different (so you return the two values that straddle the middle); otherwise, they will be the same, and you return just one value.
Caution: Contents may have been coded under pressure.
sub Return_Middle {
my $midpt = ($#_/2);
@_[int($midpt) .. int($midpt + .5)];
}
Caution: Contents may have been coded under pressure.
Re: function that returns the middle of an array
created: 2006-01-10 12:36:10
See also Re: Puzzle: The Ham Cheese Sandwich cut. (by robin) and Re: Puzzle: The Ham Cheese Sandwich cut. (by me) for a different way to find the median.