Detailed explanation of the conversion between timestamp and time string in php

PHP is a scripting language commonly used for website development and server-side programming. In PHP, timestamps are often used to represent time. The timestamp refers to the number of seconds since January 1, 1970 (00:00:00 GMT).

Although timestamps facilitate us to calculate time in the program, for ordinary users, seeing a series of numbers does not understand the time well, so the timestamp is converted into an easy-to-understand time. Format is very necessary.

This article will introduce how to convert timestamps into an easy-to-understand time format in PHP, and convert time strings into timestamps.

1. Use the date function to convert timestamps

There is a built-in function date() in PHP, which can convert timestamps into time strings in any format. The specific usage is as follows:

//将时间戳转换为日期格式，例如2021-12-31
$date = date('Y-m-d', $timestamp);

//将时间戳转换为时间格式，例如13:30:00
$time = date('H:i:s', $timestamp);

//将时间戳转换为日期和时间格式，例如2021-12-31 13:30:00
$datetime = date('Y-m-d H:i:s', $timestamp);

In the above code, Y represents the four-digit year, m represents the two-digit month, d represents a two-digit date, H represents the hour in the 24-hour format, i represents the number of minutes, and s represents the number of seconds.

Use date() to flexibly convert timestamps into different time formats.

2. Use the strtotime function to convert a time string into a timestamp

There is also a built-in function in PHPstrtotime(), which can convert a time string into a time Stamp, the specific usage method is as follows:

//将日期字符串转换为时间戳
$timestamp = strtotime('2021-12-31');

//将时间字符串转换为时间戳
$timestamp = strtotime('13:30:00');

//将日期和时间字符串转换为时间戳
$timestamp = strtotime('2021-12-31 13:30:00');

In the above code, the strtotime() function can convert a time string in any format into a timestamp, so that we can easily Calculations and conversions. It should be noted that strtotime() may fail to convert time strings in some special formats.

3. Use DateTime object to convert timestamp

In addition to using built-in functions, PHP also provides a DateTime class to handle dates and times. It can convert timestamps into DateTime objects and perform various time operations on the objects to achieve more flexible time conversion.

//将时间戳转换为DateTime对象
$datetime = new DateTime();
$datetime->setTimestamp($timestamp);

//将DateTime对象格式化为时间字符串
$date = $datetime->format('Y-m-d');
$time = $datetime->format('H:i:s');
$datetime = $datetime->format('Y-m-d H:i:s');

In the above code, we first create a new DateTime object, then use the setTimestamp() method to assign the timestamp to the object, and finally use format()Method formats objects into different time strings.

Using the DateTime object, we can perform time calculation and time comparison operations more conveniently, which is a good supplement to the built-in functions.

Conclusion

This article introduces three methods of converting timestamps into an easy-to-understand time format in PHP: using the date function, using the strtotime function, and using the DateTime object.

No matter which method is used, the timestamp can be easily converted into a time string in any format to meet the time requirements in different scenarios.

At the same time, we need to note that when using the strtotime() function, some special format time strings may fail to be converted, and special processing is required.

In general, PHP provides very rich and flexible functions in processing time. We can choose different methods to process according to our own needs.

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