Re^2: Yesterday's date

G'day hippo,

++ I agree with your approach; particularly in light of the OP's "I am not concerned about daylight savings time, time zone nor do I need HMS.".

Having said that, I believe use of the ONE_DAY constant from Time::Seconds (also a core module) would add clarity.

It's the same value:

$ perl -E 'use Time::Seconds; say ONE_DAY'
86400
[download]

It works as a direct replacement in your code:

$ perl -e '
    use strict;
    use warnings;

    use Time::Piece;
    use Time::Seconds;

    my $t = Time::Piece->strptime($ARGV[0], "%d/%m/%Y");
    printf "Date as supplied: %s\n", $t->dmy("/");
    $t = $t - ONE_DAY;
    printf "Date minus one day: %s\n", $t->dmy("/");
' 01/12/2022
Date as supplied: 01/12/2022
Date minus one day: 30/11/2022
[download]

— Ken

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Re^3: Yesterday's date by parv (Parson) on May 29, 2023 at 20:12 UTC
If `$Time::Seconds::ONE_DAY` remains constant regardless of current time, then do not see how that would add "clarity" or see its purpose. If 24 60 60 conjures up magic number, then just assign that to a local variable.	[reply] [d/l]
Re^4: Yesterday's date by kcott (Archbishop) on May 30, 2023 at 07:48 UTC
G'day parv, hippo's code uses `86400`. For those regularly working with dates and times, this might immediately leap out as the number of seconds in a day; for others, it might just be a cryptic number (which takes some thought to understand). Time::Seconds puts that number into a named constant. From its source: `use constant { ... ONE_DAY => 86_400, ... };` [download] I do believe that `ONE_DAY` is clearer than `86400`. Even more so in this particular instance where "`$t - ONE_DAY`" aligns with the text in the following `printf` statement, "`Date minus one day`". I don't have a problem with "`24 * 60 * 60`". I would have used that calculation many times myself, over the decades, where `ONE_DAY` (or equivalent) was not available. It does, however, seem like extra, unecessary work: `... my $one_day = 24 * 60 * 60; ... $t = $t - $one_day; ...` [download] Unless it's needed more than once, I probably wouldn't bother to "assign that to a local variable": `... $t = $t - 24 * 60 * 60; ...` [download] — Ken	[reply] [d/l] [select]


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