How to convert year, month and day to timestamp in php

PHP timestamp is a numeric value used to represent a date and time. Normally, we use date and time format strings to represent time, such as "YYYY-MM-DD HH:MM:SS", but when dealing with time calculations and date comparisons, using timestamps is more convenient than using date strings Much more. Therefore, this article will introduce how to convert year, month and day into timestamp in PHP to help developers better handle time-related issues.

1. strtotime() function

In PHP, there is a strtotime() function, which can convert human-readable time format into timestamp. For example, we can use the following code to convert the string "2020-07-25 15:25:00" into a timestamp:

$timestamp = strtotime('2020-07-25 15:25:00');
echo $timestamp; //输出 1595671500

The strtotime() function here will automatically parse it out according to the format in the string The corresponding timestamp value. It should be noted that the incoming parameters of the function do not necessarily contain the time part. For example, "2020-07-25" can also be converted into a timestamp.

2. mktime() function

Another way to convert the year, month and day into a timestamp is to use PHP's mktime() function. This function can convert the specified time combination of year, month, day, hour, minute, and second into a timestamp.

The following is an example to convert 15:25 on July 25, 2020 into a timestamp:

$timestamp = mktime(15, 25, 0, 7, 25, 2020);
echo $timestamp; //输出 1595671500

In the mktime() function, the first three parameters are required, respectively Represents hours, minutes, and seconds, while the last three parameters are optional and represent months, dates, and years respectively. It should be noted that the months in the mktime() function start counting from 1, not from 0.

Both of the above methods can convert the time represented by year, month and day into a timestamp. It should be noted that timestamp values ​​in PHP are usually in seconds and can be divided by 60, 3600, 86400, etc. to get minutes, hours and days. At the same time, when using timestamp comparison, special attention needs to be paid to the impact of factors such as different time zones and daylight saving time on timestamps.

The method introduced in this article is simple and easy to understand, suitable for beginners. There are many more date and time related functions in PHP, and developers can further understand and use them according to their own project needs.

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