Anonymous Monk is correct.

#!/usr/bin/env perl 
use strict;
use warnings;
use Test::More tests => 4;
use DateTime;

my $dt1 = DateTime->new ( year => 2015, month => 6, day => 1 );
my $dt2 = DateTime->new ( year => 2015, month => 6, day => 30 );

my $duration = $dt1->delta_days ($dt2);

is $duration->days, 29, 'Without delta, more than a week';
is $duration->delta_days, 29, 'With delta, more than a week';

$dt2 = DateTime->new ( year => 2015, month => 6, day => 3 );

$duration = $dt1->delta_days ($dt2);

is $duration->days, 2, 'Without delta, less than a week';
is $duration->delta_days, 2, 'With delta, less than a week';

[download]

Test 1 fails for me (with DateTime 1.20) but the others all pass. This fits with the description of the days() method on a duration which says:

These methods return numbers indicating how many of the given unit the object represents, after having done a conversion to any larger units. For example, days are first converted to weeks, and then the remainder is returned.

In reply to Re^2: Answer: How do I find the difference in days between two dates, in a cool perl way? by hippo
in thread How do I find the difference in days between two dates, in a cool perl way? by frankus

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.