How to convert online time to timestamp using PHP

PHP is a programming language widely used in web development. In recent years, with the continuous development of Internet technology, more and more online applications need to convert time into timestamps. In PHP, we can easily implement this function. This article will introduce how to convert online time to timestamp using PHP.

1. What is a timestamp?

Before explaining how to convert online time into a timestamp, we need to first understand what a timestamp is. The timestamp refers to the number of seconds that have passed since a certain moment at 0:00:00 on January 1, 1970 (UTC time zone). Timestamps are often used for things like crossing time zones and calculating time spans.

2. Use PHP to convert online time into a timestamp

In PHP, use the strtotime() function to convert a text string into a timestamp. An example is as follows:

$datetime = "2021-05-30 12:30:00";
$timestamp = strtotime($datetime);
echo $timestamp;

In the above example, we convert a time string into a timestamp and print it out using echo. The code execution result is: 1622356200.

In addition to complete date and time strings, the strtotime() function can also handle time strings in other formats, such as:

$datetime = "2021/05/30 12:30 PM";
$timestamp = strtotime($datetime);
echo $timestamp;

In the above example, we use different dates and times format, and use the echo function to output the timestamp. The code execution result is: 1622346600.

3. Time zone issue

When using the strtotime() function to convert a time string into a timestamp, pay attention to the time zone issue. Since the default time zone of PHP and the server may be different, the time zone needs to be set to the correct value. An example is as follows:

date_default_timezone_set('Asia/Shanghai');
$datetime = "2021-05-30 12:30:00";
$timestamp = strtotime($datetime);
echo $timestamp;

Use the date_default_timezone_set() function to set the time zone to Shanghai time zone (East Eighth District). This is the standard time zone representing Beijing time.

4. Summary

This article introduces how to use PHP to convert online time into a timestamp. In actual web applications, timestamps are often used for data comparison and time calculation. By learning the knowledge introduced in this article, you can better master the timestamp processing skills in PHP.

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