PHP date format Summary of PHP date operation skills

The examples in this article summarize PHP date operation techniques. Share it with everyone for your reference, the details are as follows:

1. PHP converts the date format obtained in the form into a unified format

2015-9-9 is uniformly converted into 2015-09-09, so that it is unified in the database Format, convenient for future query

$year = "2015";
$month = "9";
$day = "09";
var_dump(checkdate($month,$day, $year));//月和日带有前导0都是符合格式的
if(checkdate($month,$day, $year)===false){
  exit('error');
};
$unixtime = mktime(2,2,2,$month,$day,$year);//目的是交给php转换成月和日都带有前导0的格式统一的格式存储在数据库方便以后查询
var_dump(date("Y-m-d",$unixtime));
////交给php转换成时间戳,然后反转回来

2. Get the start timestamp and end timestamp of the previous day

The original idea is:

First use date to get the year, month and day of the day. Get it separately. The year is 2015, the month is 9, the day is 28
, and then subtract 1. But a problem arises.

What if today is the 1st. Subtract 1 and it becomes 0. The last month could be 28 days or it could be 30 days.

In this way, first get the timestamp of the previous day. Let php automatically calculate it.

strtotime("-1 day");
//得到上一天的时间戳,现在是几点就得到上一天这个时间点的时间戳,用这种方式好处是解决了上面问题,php会自动去计算上个月多少天

<&#63;php
header("Content-type:text/html;charset=utf-8");
date_default_timezone_set("Asia/Shanghai");//设置时区
$last_day = strtotime("-1 day");//得到上一天的时间戳,现在是几点就得到上一天这个时间点的时间戳
//通过时间戳得到年月日,以便mktime使用
$year = date("Y",$last_day);
$month = date("m",$last_day);
$day = date("d",$last_day);
$last_day_begin = mktime(0,0,0,$month,$day,$year);//昨天的一天开始的时间戳
$last_day_end = mktime(23,59,59,$month,$day,$year);
echo '昨天开始时间戳:';
var_dump($last_day_begin);
echo date('Y-m-d H:i:s',$last_day_begin);
echo '<br />';
echo '昨天结束时间戳:';
var_dump($last_day_end);
echo date('Y-m-d H:i:s',$last_day_end);
echo '<br />';
echo ($last_day_end-$last_day_begin)/(60*60);//恰好24个小时

Readers who are interested in more PHP-related content can check out the special topics of this site: "Summary of PHP Date and Time Usage", "Introduction Tutorial on PHP Object-Oriented Programming", "Summary of PHP Mathematical Operation Skills" , "Summary of PHP operating office document skills (including word, excel, access, ppt)", "Complete PHP array (Array) operation skills", "PHP data structure and algorithm tutorial", "php programming algorithm summary", "php Summary of Regular Expression Usage" and "Summary of Common Database Operation Skills in PHP"

I hope this article will be helpful to everyone in PHP programming.

The above introduces the PHP date format and a summary of PHP date operation skills, including the PHP date format. I hope it will be helpful to friends who are interested in PHP tutorials.