Re^2: Calculating statistical median

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Hi.

Is there a special reason for the array reference? Versus this?

sub mean {
    my $result;
    foreach (@_) { $result += $_ }
    return $result / @_;
}

my @points = qw(1 2 3 4);

print mean @points;
[download]

Comment on Re^2: Calculating statistical median Download Code

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Re^3: Calculating statistical median by dirac (Beadle) on Jul 14, 2005 at 03:07 UTC
Copying an array or hash into @_ takes time. Passing arrays and hashes by reference is straightforward. See Benchmark If you want median: `sub median { $_[0]->[ @{$_[0]} / 2 ] } my @points = 0..100; print median(\@points), "\n";` [download]	[reply] [d/l]
Re^4: Calculating statistical median by jimbojones (Friar) on Jul 14, 2005 at 09:51 UTC
Hi Thanks. Didn't know about the speed issue. - j	[reply]
Re^4: Calculating statistical median by Anonymous Monk on Apr 22, 2016 at 09:59 UTC
It should sort the array before calculating median this way. Besides that it does not handle the array with even elements correctly.	[reply]
Re^4: Calculating statistical median by Anonymous Monk on May 02, 2016 at 10:04 UTC
This calculates median only if @points is already truly ordered.	[reply]
Re^4: Calculating statistical median by Anonymous Monk on Jun 16, 2017 at 05:49 UTC
This sample has a bug: if input array is not sorted, the result is incorrect. `$ cat median.pl sub median { $_[0]->[ @{$_[0]} / 2 ] } my @sample=(9, 1, 2, 3, 4, 8, 7, 6, 5); my @sorted; @sorted=sort @sample; print median(\@sample),"\n"; print median(\@sorted),"\n"; $ perl median.pl 4 5 $` [download] Should be `5 5` [download]	[reply] [d/l] [select]

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