Detailed explanation of php UNIX timestamp usage

This article mainly introduces the usage of php UNIX timestamp, and analyzes the related functions and usage skills of php Unix timestamp in the form of examples. Friends in need can refer to it

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The timestamp is the creation, modification, and access time in the file attributes. The digital timestamp service is one of the Web website security services that can provide security protection for the date and time information of electronic files.

The advantage of timestamp is:

The encrypted value can be changed to prevent the value from being stolen and illegally reused, and plays the role of encryption. . Timestamps mainly rely on time and generate a unique value within an agreed period of time.

UNIX timestamp

In the UNIX system, the date and time are expressed as the time from 0:00 on January 1, 1970 to the current moment Number of seconds. This time is called a UNIX timestamp and is represented as a 32-bit binary number. This time representation method is supported in different operating systems. The same time is represented by the same UNIX timestamp in UNIX and Windows, so there is no need to convert in different systems.

The current UNIX timestamp is represented by a 32-bit binary number, and the 32-bit binary value range is (-2147483648~2147483647). Since the system does not support negative timestamps, the current UNIX timestamp can represent the maximum The time is 3:14:07 on January 19, 2038, and the timestamp of this moment is 2147483647. After this time, the number of binary digits of the UNIX timestamp needs to be extended.

PHP Gets the timestamp of a specified date

The mktime() function is used in PHP to convert a time into a UNIX timestamp value.

The syntax is as follows

mktime(hour,minute,second,month,day,year,is_dst)

##hourOptional. Specified hours. minuteOptional. Specified minutes. secondOptional. Specifies seconds. monthOptional. Specifies the numeric month. day Optional. Specify days.

Parameters	Description
year	Optional. Specified year. On some systems, legal values ​​are between 1901 - 2038. However, this limitation no longer exists in PHP 5.
is_dst	Optional. Set to 1 if the time is during Daylight Saving Time (DST), 0 otherwise, or -1 if unknown. Since 5.1.0, the is_dst parameter is deprecated. Therefore the new time zone handling features should be used.

For example:

echo "时间戳：".mktime().&#39;<br>&#39;;//返回当前时间戳
echo "任意日期：".date("Y-m-d",mktime(0,0,0,2,21,1996)).&#39;<br>&#39;;
echo "当前日期: ".date("Y-m-d",mktime()).&#39;<br>&#39;;

The running result is:

时间戳：1458979695
任意日期：1996-02-21
当前日期: 2016-03-26

Get the current timestamp

PHP gets the current UNIX timestamp through the time() function.

The syntax is as follows:

int time(void);

This function has no parameters and the return value is the integer value of the UNIX timestamp.

For example:

echo time()."<br>";//输出当前时间戳
$nextWeek = time()+(7*24*60*60);//一个星期七天，一天24小时，一个小时60分，一分60秒
echo "Now: ".date("Y-m-d")."<br>";
echo "Next Week: ".date("Y-m-d",$nextWeek);

The running result is

1458980073
Now: 2016-03-26
Next Week: 2016-04-02

will The date and time description of English text is parsed into a UNIX timestamp

strtotime() function parses the date and time description of any English text into a Unix timestamp.

Syntax

strtotime(time,now)

Parameters	Description
time	Specifies the time string to be parsed.
now	The timestamp used to calculate the return value. If this parameter is omitted, the current time is used.

For example:

echo(strtotime("now")).&#39;<br>&#39;;
echo(strtotime("3 October 2005")).&#39;<br>&#39;;
echo(strtotime("+5 hours")).&#39;<br>&#39;;
echo(strtotime("+1 week")).&#39;<br>&#39;;
echo(strtotime("+1 week 3 days 7 hours 5 seconds")).&#39;<br>&#39;;
echo(strtotime("next Monday")).&#39;<br>&#39;;
echo(strtotime("last Sunday")).&#39;<br>&#39;;

The running result is:

1458980310
1128268800
1458998310
1459585110
1459869515
1459094400
1458403200

If you want to view the time corresponding to this timestamp, for example:

echo date("Y-m-d H:i:s",strtotime("now")).&#39;<br>&#39;;
echo date("Y-m-d H:i:s",strtotime("next Thursday")).&#39;<br>&#39;;

The running result is:

2016-03-26 16:21:32
2016-03-31 00:00:00

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