如何使用本地时间获取昨天的日期? [英] How do I get yesterday's date using localtime?

问题描述

如何调整它以使用本地时间获取昨天的日期?

How do I tweak this to get yesterday's date using localtime?

use strict;

sub spGetCurrentDateTime;
print spGetCurrentDateTime;

sub spGetCurrentDateTime {
my ($sec, $min, $hour, $mday, $mon, $year) = localtime();
my @abbr = qw( Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec );
my $currentDateTime = sprintf "%s %02d %4d", $abbr[$mon], $mday, $year+1900; #Returns => 'Aug 17 2010' 
return $currentDateTime;
}

~

推荐答案

DST 问题可以通过从今天中午而不是当前时间开始 3600 来解决:

The DST problem can be worked around by taking 3600s from midday today instead of the current time:

#!/usr/bin/perl
use strict;
use warnings;
use Time::Local;

sub spGetYesterdaysDate;
print spGetYesterdaysDate;

sub spGetYesterdaysDate {
my ($sec, $min, $hour, $mday, $mon, $year) = localtime();
my $yesterday_midday=timelocal(0,0,12,$mday,$mon,$year) - 24*60*60;
($sec, $min, $hour, $mday, $mon, $year) = localtime($yesterday_midday);
my @abbr = qw( Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec );
my $YesterdaysDate = sprintf "%s %02d %4d", $abbr[$mon], $mday, $year+1900;
return $YesterdaysDate;
}

鉴于 Chas 建议的 strftime 解决方案的未指定"记录行为，如果您无法跨多个平台测试预期但不保证的结果，这种方法可能会更好.

In light of the "unspecified" documented behaviour of the strftime solution suggested by Chas, this approach might be better if you're not able to test for expected-but-not-guaranteed results across multiple platforms.

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