perl - 如何计算 Perl 中的 DateTime 差异？

Question

use DateTime ;

my $date = "2010-08-02 09:10:08";

my $dt = DateTime->now( time_zone => 'local' )->set_time_zone('floating');
print $dt->subtract_datetime($date);

它不起作用；问题是什么？

错误信息是:

Can't call method "time_zone" without a package or object reference at
/opt/perl/perl5.12/lib/site_perl/5.12.0/x86_64-linux/DateTime.pm line 1338

Answer 1

您需要先将日期字符串转换为 DateTime 对象，使用
自定义格式或许多可用的 DateTime::Format::* 库之一。
您使用的是数据库中常用的格式，所以我选择了 MySQL
格式化程序(然后为最终结果定义自定义持续时间格式化程序，
从示例中复制
DateTime::Format::Duration ):

use DateTime;
use DateTime::Format::MySQL;
use DateTime::Format::Duration;

my $date = "2010-08-02 09:10:08";

my $dt1 = DateTime->now(time_zone => 'floating', formatter => 'DateTime::Format::MySQL');
my $dt2 = DateTime::Format::MySQL->parse_datetime($date);

my $duration = $dt1 - $dt2;
my $format = DateTime::Format::Duration->new(
    pattern => '%Y years, %m months, %e days, %H hours, %M minutes, %S seconds'
);
print $format->format_duration($duration);

# prints:
# 0 years, 00 months, 0 days, 00 hours, 421 minutes, 03 seconds