Here's a simplified version of a pattern I come across every so often that bugs me: you're reading from a stream of unknown length, you need to do "something" at every Nth iteration, and N is pretty much never an even divisor, so there are always leftovers, which makes for a clumsy re-use of the "something", like so:

use 5.014;
use warnings;

my ($sum, $count) = (0,0);

while (<DATA>) {
    $sum += $_;
    $count++;
    if ($count == 5) {
        printf "Sum: %4d, count: %2d, mean: %5.1f\n", 
            $sum, $count, $sum/$count;
        $sum = 0;
        $count = 0;
    }
}
printf "Sum: %4d, count: %2d, mean: %5.1f\n", 
    $sum, $count, $sum/$count;

__DATA__
61
23
30
444
368
438
467
44
812
430
992
469

[download]

This outputs:

      Sum:  926, count:  5, mean: 185.2
      Sum: 2191, count:  5, mean: 438.2
Final Sum: 1461, count:  2, mean: 730.5

[download]

Often, the "something" (the printf in my example, but could be a few statements in length) doesn't warrant putting it into a sub (and paying the function call overhead every Nth time through the main loop), but neither do I like having to copy/paste it just to catch the leftovers after the loop exit.

Is there a good way to refactor this so I don't have to repeat the printf, without sticking it in a sub?

In reply to Refactor this to eliminate the duplicated printf? by wanna_code_perl

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