What is the php timestamp?

PHP timestamp number

PHP is a high-level programming language widely used in the field of web development. In PHP, timestamp is a very important concept, used to represent a specific moment in time. A timestamp refers to a number that represents time, usually counting from a fixed point in time (such as January 1, 1970 00:00:00).

In PHP, timestamp is represented by an integer value, usually a 10-digit number. This number represents the number of seconds since the Unix Epoch (January 1, 1970 00:00:00 UTC). For example, if we now run the following code:

echo time();

it will output an integer value similar to 1633064231. This integer value represents the number of seconds since the Unix Epoch.

In addition to the default 10-bit timestamp, PHP also supports other formats of timestamps, including 13-bit and 16-bit timestamps.

The 13-digit timestamp refers to the number of milliseconds since the Unix Epoch. Timestamps in milliseconds are more precise and are therefore more common in applications that require millisecond accuracy.

We can get the 13-digit timestamp through the following code:

echo round(microtime(true) * 1000);

This code will output a 13-digit timestamp in a format similar to 1633064231234. This number represents the number of milliseconds since the Unix Epoch.

The 16-bit timestamp refers to the number of microseconds since the Unix Epoch. Timestamps in microseconds are more precise and are therefore more common in applications that require microsecond accuracy. However, PHP's time() function does not support 16-bit timestamps, so we need to use other methods to obtain 16-bit timestamps.

We can get the 16-digit timestamp through the following code:

function get_microtime() {
    list($usec, $sec) = explode(" ", microtime());
    return str_replace('.', '', (string) $sec) . str_pad((string) $usec, 6, '0', STR_PAD_RIGHT);
}
echo get_microtime();

This code will output a 16-digit timestamp in a format similar to 1633064231234567. This number represents the number of microseconds since the Unix Epoch.

Summary:

In PHP, timestamp is a very important concept.

The default timestamp is represented by 10 digits.

13-digit timestamp represents the number of milliseconds since the beginning of the Unix Epoch.

16-bit timestamp represents the number of microseconds since the beginning of the Unix Epoch.

These different formats of timestamps have their application value in different application scenarios.

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