CODEWITHSUNDEEP
perl
Liam Fell
Liam Fell

Reputation: 1320

Perl, issue converting time stamp to readable date

I have the following one liner, this should convert the date from one week ago today to a readable format.

my $week_ago = strftime("%Y-%m-%d", time - 604800);

However I get the following error:

Usage: POSIX::strftime(fmt, sec, min, hour, mday, mon, year, wday = -1, yday = -1, isdst = -1)

Can anyone suggest what the issue is here? From my understanding, strftime should convert a time stamp to a readable date.

Upvotes: 1

Views: 149

Answers (2)

simbabque
simbabque

Reputation: 54381

As your error message says, POSIX's strftime takes a list of vaules, not a unix timestamp. You need to call localtime or gmtime before you call it.

 my $one_minute_ago = strftime("%Y-%m-%d", localtime(time - 60));

The above example is fine if you are doing date math with short amounts below one day. Everything above that is error-prone. For your one week ago scenario, use sobrique's answer instead.

Upvotes: 4

Sobrique
Sobrique

Reputation: 53508

Use Time::Piece. It's a core module that replaces localtime (and gmtime) but turns it into a much more useful form. 

use Time::Piece;
my $week_ago = localtime() - 604800;
print $week_ago -> strftime("%Y-%m-%d");

Note - both localtime and gmtime now return a Time::Piece object, which means you can do numeric comparisons with it too.

You can also for clarity - import Time::Seconds and use it to define more useful constants (like ONE_DAY and ONE_WEEK) as noted by Borodin in the comments.

use Time::Piece;
use Time::Seconds qw ( ONE_WEEK ); 
my $week_ago = localtime() - ONE_WEEK;

Upvotes: 4

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