How to convert "year, month, day" into timestamp in php

With the continuous development of Internet technology, PHP has become a very popular web development language. In PHP development, timestamp is a very important data type. In some applications that need to calculate date and time, using timestamps can greatly simplify code writing and maintenance, and improve code performance. In this article, we will detail how to convert year, month and day into timestamp.

1. The concept of timestamp
   In computer science and the Unix operating system, a timestamp represents the current moment as since 00:00 on January 1, 1970: A number of seconds or milliseconds since 00 GMT. Timestamp is a universal time representation that is widely used in database operations, file systems, and various applications.
2. How to process timestamps in PHP

In PHP, there are two very commonly used functions that can be used to process timestamps:

• time()
• strtotime()

The time() function returns the current Unix timestamp, or you can call the date() function to convert the timestamp into a date String. The strtotime() function can convert a date string into a Unix timestamp.

3. How to convert year, month and day into timestamp

The method to convert year, month and day into timestamp is very simple, you can use strtotime () function to perform conversion. Just pass the date string as a parameter of the function. For example, the following code converts the date string "2019-09-01" into a timestamp:

$timestamp = strtotime('2019-09-01');

If you need to convert a date string with time into a timestamp, you can add a time value to the date string That’s it. For example, the following code converts the date string "2019-09-01 12:00:00" into a timestamp:

$timestamp = strtotime('2019-09-01 12:00:00');

If you need to convert a date string containing time zone information into a timestamp, you can use DateTime class to handle. For example, the following code converts the date string "2019-09-01T12:00:00 08:00" containing time zone information into a timestamp:

$datetime = new DateTime('2019-09-01T12:00:00+08:00');
$timestamp = $datetime->format('U');

4. Summary

Converting year, month and day into timestamp in PHP is very simple, just use the strtotime() function. In actual applications, using timestamps can greatly simplify code writing and maintenance, and improve code performance. At the same time, timestamp is also a universal time representation that can easily interact with other applications.

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