如何在Perl中更改日期時間值的時區？

Question

使用此功能：

perl -e 'use Time::Local; print timelocal("00","00","00","01","01","2000"),"\n";' 

它會返回一個epochtime - 但只有在格​​林尼治標準時間 - 如果我想要的結果在GMT + 1（這是系統的本地時間（TZ）），我需要做什麼改變？

由於提前，

安德斯

Answer 1

只有一個基於UTC的epochtime的標準定義，而不是不同時區的不同epochtimes。

如果你想找到offset between gmtime and localtime，使用

use Time::Local; 
@t = localtime(time); 
$gmt_offset_in_seconds = timegm(@t) - timelocal(@t); 

Answer 2

你只需要設置時區。嘗試：

 
env TZ=UTC+1 perl -e 'use Time::Local; print timelocal("00","00","00","01","01","2000"),"\n";' 

Answer 3

Time::Local::timelocal是localtime倒數。其結果將是在主機的本地時間：

$ perl -MTime::Local -le \ 
    'print scalar localtime timelocal "00","00","00","01","01","2000"' 
Tue Feb 1 00:00:00 2000

你想對應於該localtime的gmtime？

$ perl -MTime::Local' -le \ 
    'print scalar gmtime timelocal "00","00","00","01","01","2000"' 
Mon Jan 31 23:00:00 2000

你想它周圍的其他方式，對應於該gmtime的localtime？

$ perl -MTime::Local -le \ 
    'print scalar localtime timegm "00","00","00","01","01","2000"' 
Tue Feb 1 01:00:00 2000

Answer 4

雖然Time :: Local是一個合理的解決方案，但您最好使用更現代的DateTime面向對象模塊。以下是一個示例：

use strict; 
use DateTime; 
my $dt = DateTime->now; 
print $dt->epoch, "\n"; 

對於時區，可以使用DateTime :: TimeZone模塊。

use strict; 
use DateTime; 
use DateTime::TimeZone; 

my $dt = DateTime->now; 
my $tz = DateTime::TimeZone->new(name => "local"); 

$dt->add(seconds => $tz->offset_for_datetime($dt)); 

print $dt->epoch, "\n"; 

CPAN鏈接：

DateTime

Answer 5

use DateTime; 
my $dt = DateTime->now; 
$dt->set_time_zone('Europe/Madrid'); 

Answer 6

的其他例子基於DateTime::Format::Strptime

use strict; 
use warnings; 
use v5.10; 
use DateTime::Format::Strptime; 

my $s = "2016-12-22T06:16:29.798Z"; 
my $p = DateTime::Format::Strptime->new(
    pattern => "%Y-%m-%dT%T.%NZ", 
    time_zone => "UTC" 
); 

my $dt = $p->parse_datetime($s);  
$dt->set_time_zone("Europe/Berlin"); 
say join ' ', $dt->ymd, $dt->hms; # shows 2016-12-22 07:16:29