How to convert time format to timestamp in PHP

PHP is a process programming language widely used in Web development. In PHP development, time conversion is one of the common operations. This article will introduce how to convert the time format in PHP into a timestamp. A timestamp represents time as the number of seconds since the Unix epoch (i.e. January 1, 1970 00:00:00 UTC) and is a universal time representation.

1. Use the strtotime() function to convert the time format into a timestamp

In PHP, the strtotime() function can convert the time format into a timestamp. Its syntax is as follows:

strtotime ( string $time [, int $now = time() ] ) : int|false

Among them, time is the time format that needs to be converted, and now is an optional parameter, indicating the base time used for conversion. If the now parameter is not passed in, the current time will be used as the basis.

For example:

$time = '2021-12-31 23:59:59';
$timestamp = strtotime($time);
echo $timestamp;

The output result is:

1640995199

This timestamp represents the seconds relative to the Unix epoch at 23:59:59 on December 31, 2021 number.

2. Use DateTime class to convert time format to timestamp

The DateTime class in PHP provides a more convenient and readable way to handle time and date, it can Convert the time format to a DateTime object through the createFromFormat() method, and then obtain the timestamp through the getTimestamp() method.

For example:

$time = '2021-12-31 23:59:59';
$date = DateTime::createFromFormat('Y-m-d H:i:s', $time);
$timestamp = $date->getTimestamp();
echo $timestamp;

The output result is also:

1640995199

This way looks more concise and easier to read.

When dealing with time conversion, you need to pay attention to the time zone issue. The timestamp in PHP uses UTC standard time. If you need to convert the time in other time zones, you need to use the DateTimeZone class to make adjustments.

To sum up, this article introduces two ways to convert the time format in PHP into a timestamp: using the strtotime() function and the DateTime class. Use these methods to easily convert time formats into timestamps, making it easier to compare and calculate times. At the same time, you need to consider the adaptation of time zones and time strings in different formats before use.

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