PHP日期在减去一个月后返回错误的月份

Question

Current Date is 29th March 2017

When I subtract 2 months using PHP and I get January

$prevmonth = date('M', strtotime('-2 months'));
echo $prevmonth;

But when I subtract 1 month it gives March

$prevmonth = date('M', strtotime('-1 months'));
echo $prevmonth;

Answer 1

strtotime() uses 30 day months and there are only 28 in days in February (this year) so will not yield a valid date in February. You could use the current day d or j and subtract that which will always put you in the previous month (-29 days):

$prevmonth = date('M', strtotime('-' . date('d') . ' days'));

This will get December from January as well.