What is timestamp in php? How to get it?

In order to implement any time-related functions, timestamps must be used. In PHP, a timestamp is a way of representing each moment in time in your computer. A timestamp is a numeric value that represents a specified date and time, that is, the number of seconds that have elapsed since January 1, 1970 00:00:00 UTC (Coordinated Universal Time).

PHP's timestamp is an integer, representing the number of seconds from 0:00:00 on January 1, 1970 (GMT) to the current time. Because generally, the range of UNIX timestamps we use is a positive 32-bit integer, that is, from 0:00:00 on January 1, 1970 to 3:14:07 on January 19, 2038.

In PHP, we can get the current timestamp through the function time(). The example is as follows:

$currentTimestamp = time(); // 获取当前时间戳
echo $currentTimestamp; // 输出：1612828285（以秒为单位）

In addition, we can also get the time in the specified area by setting the time zone. Stamp, the example is as follows:

date_default_timezone_set('Asia/Shanghai'); // 设置时区为上海
$timestampChina = time(); // 获取中国标准时间的时间戳
echo $timestampChina; // 输出：1612828285（以秒为单位）

By comparing two timestamps, we can easily calculate the difference between the two times, the example is as follows:

$timestamp1 = strtotime('2021-02-01 13:00:00'); // 获取时间戳1
$timestamp2 = strtotime('2021-02-01 18:00:00'); // 获取时间戳2
$diffSeconds = abs($timestamp2 - $timestamp1); // 计算两个时间戳之间的秒数差值
echo $diffSeconds; // 输出：18000（表示相差5个小时）

In addition to calculating the time difference , we can also format time through timestamp, for example, format timestamp into a specified date and time string, the example is as follows:

$timestamp = time(); // 获取当前时间戳
$dateString = date('Y-m-d H:i:s', $timestamp); // 将时间戳格式化为日期时间字符串
echo $dateString; // 输出：2021-02-09 10:31:25

Of course, in PHP, we can also use other dates Time functions, such as strtotime(), date(), strftime(), etc., effectively improve the efficiency of our use of timestamps.

To sum up, PHP timestamp is a way to represent each moment in the computer. It is an integer in seconds starting from January 1, 1970 (GMT). We can use it to Perform a series of time-related operations such as timestamp calculation, timestamp formatting, and timestamp comparison.

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