Examples of how to use time conversion functions in PHP

In PHP, timestamp is a very important data type, which represents a specific date and time. PHP provides some convenient built-in functions for working with times and dates, including functions for converting dates to timestamps. In this article, we will detail how to use time conversion functions in PHP.

1. The concept and purpose of timestamp

A timestamp refers to the time between a specific date and time and the Unix epoch (i.e. January 1, 1970 00:00:00 UTC time) The difference in seconds. Timestamps can represent any specific date and time, making it easy to convert times into numbers for easy calculations and comparisons.

In PHP, timestamps are widely used to process time and dates, such as calculating the time difference between different time zones, and displaying the date and time of dynamic data on websites, etc.

2. How to convert time into timestamp

In PHP, there are two main functions that can convert time into timestamp, they are strtotime() and mktime().

1. strtotime() function

The strtotime() function is to convert a date string into a Unix timestamp. Its syntax is as follows:

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

Among them, the $time parameter specifies the date string that needs to be converted, and the $now parameter is optional and is used to specify the current time used when converting the timestamp into a date string. If the $now parameter is not specified, the current time is used by default.

Here is an example of using the strtotime() function to convert a date string to a timestamp:

$timestamp = strtotime('2019-07-01 10:30:30');
echo $timestamp; // 输出：1561954230

2. mktime() function

mktime( ) function creates a Unix timestamp based on the specified date and time. Its syntax is as follows:

mktime ([ int $hour = date("H") [, int $minute = date("i") [, int $second = date("s") [, int $month = date("n") [, int $day = date("j") [, int $year = date("Y") [, int $is_dst = -1 ]]]]]]] ) : int|false

Among them, $hour, $minute and $second parameters are used to specify hours, minutes and seconds, $month, The $day and $year parameters specify the month, day, and year. The $is_dst parameter is used to indicate whether to consider daylight saving time.

The following is an example of using the mktime() function to create a timestamp:

$timestamp = mktime(10, 30, 30, 7, 1, 2019);
echo $timestamp; // 输出：1561954230

3. How to convert a timestamp into time

In PHP, you can use date( ) function formats a timestamp into a specified date and time format. The syntax of the date() function is as follows:

date ( string $format [, int $timestamp = time() ] ) : string

Among them, the $format parameter is used to specify the format of the date and time, and the $timestamp parameter is optional and is used to specify the timestamp that needs to be converted. If the $timestamp parameter is not specified, the current time is used by default.

The following is an example of using the date() function to convert a timestamp into a time:

$timestamp = time(); // 获取当前时间戳
echo date('Y年m月d日 H时i分s秒', $timestamp); // 输出：2022年10月01日 15时13分24秒

4. Summary

In PHP, timestamp is a very important Data type that represents a specific date and time. PHP provides some built-in functions to conveniently convert time and date to timestamps, and convert timestamps to time in a specified format. Commonly used functions include strtotime(), mktime() and date(). Use these functions to easily handle time and date for better building of PHP applications.

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