moving average

I was hacking up a graphics display program, and I needed to add a moving-average line along with a data plot. Came up with this simple little few-liner.

my $AVERAGE_OVER = 10; # number of periods for moving average
...
my @averages = do {
  my $sum = 0;
  my @summers = ();
  map {
    $sum += $_;
    push @summers, $_;
    $sum -= shift @summers if @summers > $AVERAGE_OVER;
    $sum / @summers;
  } @data; # THIS IS THE INPUT DATA
};
[download]

Comment on moving average Download Code

Replies are listed 'Best First'.
Re: moving average by I0 (Priest) on Dec 25, 2000 at 17:17 UTC
It may not matter for a graphics display but if @data values are floating, beware of accumulated round off errors.	[reply]
Re: moving average by extremely (Priest) on Dec 25, 2000 at 12:38 UTC
Now that is just the best use of a "do block" I've seen all year. I'd have done that as a sub, everytime. You win the "Baby Bear" award for the year. =) It's not too hot, it's not too cold, that code is exactly right. -- $you = new YOU; honk() if $you->love(perl)	[reply]