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You want to know how many days until a certain date, or how long between two dates. Perl has many different modules to handle dates.
The following program uses the
Time::Local module to determine the age (in seconds) of
someone born on the 3rd of May in 1980.
You supply the
timelocal() subroutine a date as a six-element array, and it returns
the corresponding value in seconds since the system epoch.
Time::Local expects that the value for the day of the month is a number in
the range 1 to 31, while the value for the month itself is a number in the range 0 to 11,
(since it is considered the number of months since January).
#!/usr/bin/perl use strict; use warnings; use Time::Local; my @today = localtime(); my $time = timelocal(@today); my @birthday = (0, 54, 23, 3, 4, 1980); my $birthtime = timelocal(@birthday); print "My age in seconds = " . ($time - $birthtime) . "\n"; exit 0;
The output of this program is something like:
My age in seconds = 843513440
Date::Calc module provides lots of great date and time functionality. The
following example uses the
Delta_Days() method to calculate how old the same
person is in days (in other words, it calculates the days between two dates):
#!/usr/bin/perl use strict; use warnings; use Date::Calc qw(Delta_Days); my @today = (localtime)[5,4,3]; $today += 1900; $today++; my @birthday = (1980, 4, 3); my $days = Delta_Days(@birthday, @today); print "I am $days days old\n"; exit 0;
The output of this example is something like:
I am 9793 days old
perldoc Time::Local perldoc Date::Calc perldoc Date::Manip perldoc -q "How can I compare two dates and find the difference?" perldoc DateTime