php 日期相关的类 DateInterval DateTimeZone DatePeriod

* DateInterval

add($interval);
echo $datetime->format('Y-m-d H:i:s').PHP_EOL;

// + 1month
$datetime->add(
    new DateInterval('P1M')
);
echo $datetime->format('Y-m-d H:i:s').PHP_EOL;

// -1month -2weeks
$datetime->add(
    \DateInterval::createFromDateString("-1 month -2 weeks")
);
echo $datetime->format('Y-m-d H:i:s').PHP_EOL;

echo '------------------',PHP_EOL;
// start, interval, recurrences
$datePeriod = new \DatePeriod(
    $datetime,
    \DateInterval::createFromDateString('-1 day'),
    3
);
foreach ($datePeriod as $date) {
    echo $date->format('Y-m-d'),PHP_EOL;
}

　　

　　output: