This seems to be a little better, benchmarkwise (it assumes days are numbered 0-6):
use strict;

# Days start at 0, just like arrays
my $start_day = 6;
my $days = 7;
my @cnts = daycounts($start_day, $days);
for (0..6) {
 print "$_: $cnts[$_]\n";
}
sub daycounts {
 use integer;
 my $start_day = shift;
 my $days = shift;
 my $end_day = ($start_day + $days) % 7;
 my $compare = ($start_day <= $end_day)
  ? sub { my $num = shift; $start_day <= $num and $num <= $end_day }
  : sub { my $num = shift; $num <= $end_day or $start_day <= $num };
 my @adjust = map { $compare->($_)? 1 : 0 } 0..6;
 my $cnts = $days / 7;
 map { $cnts + $adjust[$_] } 0..6;
}

[download]
Update: There. fixed. Except now its slower :( though if you unroll that sub reference/dereference and map into two separate maps then its faster :)

Another update: Re:ThuG's reply - I made the assumption that zero days means just the start day, and 1 day means the start day and the next day, so 17 days from Wednesday would take you to Saturday, not Friday. So just subtract one from $days coming in to get what you expect.

In reply to Re: How Many Mondays in Date Range? by runrig
in thread How Many Mondays in Date Range? by THuG

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.