CODEWITHSUNDEEP
perldatetime
user2007843
user2007843

Reputation: 609

check if date is valid

In my program I have the user input a date in the format of "Month Day" (example May 25) and I want to be able to print an error message if it is an invalid date (example February 30).

So here's some code

$start_date = ARGV[0];
my $year = DateTime->now->year;                                          # adds a year to the date
my $date_parser = DateTime::Format::Strptime->new(pattern => '%Y %B %d', # YYYY Month DD
);
my $start_epoch = $date_parser->parse_datetime("$year $start_date")->epoch();

Right after this I need some kind of if statement right?

Upvotes: 1

Views: 1836

Answers (2)

Huang Chen
Huang Chen

Reputation: 1205

From perlmonks:

use Time::Local;
my $date = ' 19990230'; # 30th Feb 1999
$date =~ s/\s+$//;
$date =~ s/^\s*//;
my ($year, $month, $day) = unpack "A4 A2 A2", $date;
eval{ 
    timelocal(0,0,0,$day, $month-1, $year); # dies in case of bad date
+ 
    1;
} or print "Bad date: $@";

This should do you justice

Upvotes: 0

Sobrique
Sobrique

Reputation: 53478

If the date is invalid, then the parser will return undef. You will see this quite quickly if you do:

my $start_date = "Feb 30";
my $year = DateTime->now->year;                                          # adds a year to the date
my $date_parser = DateTime::Format::Strptime->new(pattern => '%Y %B %d', # YYYY Month DD
);
my $start_epoch = $date_parser->parse_datetime("$year $start_date")->epoch();

The solution:

my $parsed =  $date_parser->parse_datetime("$year $start_date");
if ( not defined $parsed ) { print "Error - invalid date\n"; }

Upvotes: 3

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