Note that this approach will have a problem for those days with less than 24 hours

I would be interested to see a test case showing that, if you could provide one. The tests I tried all worked fine, even on 23-hour days. That's why I posted it as-is rather than trying to work around a problem which didn't appear to be there.

Here's my trivial test script for comparison:

use strict;
use warnings;

use Time::Piece;
use Test::More tests => 366 * 2 + 1;

my $dstr = '01/01/2023';

for (1 .. 366) {
    my $t = Time::Piece->strptime ($dstr, '%d/%m/%Y');
    my $nt = $t - 86400;
    isnt $dstr, $nt->dmy ('/');
    my $ddiff = $t->mday - $nt->mday;
    ok ($ddiff < 0 || $ddiff == 1), '1 day different or month wrap';
    $dstr = $nt->dmy ('/');
}
is $dstr, '31/12/2021';

[download]

🦛

In reply to Re^3: Yesterday's date by hippo
in thread Yesterday's date by jpys

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