Some commonly used PHP time functions and their usage

In PHP development, we often need to convert timestamps or date strings into readable date and time formats. PHP comes with many powerful time functions that can help us easily convert time formats. The following will introduce some commonly used PHP time functions and their usage.

1. date()

date() is one of the most commonly used time functions in PHP. It can convert timestamps into date and time strings in various formats. . The basic syntax of this function is as follows:

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

Among them, the $format parameter is required. It represents the date and time format required for output, and various formatting characters can be used. As shown in the following table:

##d日(two persons)20HHour (24 system)19iMinute (two digits)35sSeconds (two digits)59wWeek (digit)0 (Sunday) - 6 (Saturday)

Format characters	Description	Example
Y	Four-digit year	2021
m	Month (two digits)	04

The $timestamp parameter is optional and defaults to the current timestamp. Here are some examples of practical applications:

// 输出 2021-04-20
echo date("Y-m-d", time());

// 输出 2021年4月20日 星期二 19:35:59
echo date("Y年n月j日 l H:i:s");

// 输出 04/20/2021
echo date("m/d/Y");

// 输出 2021年04月20日
echo date("Y年m月d日");

strtotime()

The strtotime() function is a commonly used function to convert date and time strings into timestamps. It recognizes a large number of date and time formats, including ISO 8601 format. The syntax format of the function is as follows:

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

Among them, the $time parameter is required and represents the date and time string to be converted. The $now parameter is optional and defaults to the current timestamp. The function converts a datetime string into a timestamp. Here are some examples of practical applications:

// 输出 1618934400
echo strtotime("20 April 2021");

// 输出 1618858800
echo strtotime("Yesterday");

// 输出 1618783200
echo strtotime("2021-04-19 13:20:00");

// 输出 1618860840
echo strtotime("+1 day 1 hour 30 minutes");

getdate()

getdate() function converts a timestamp into a date array. The syntax of this function is as follows:

getdate ([ int $timestamp = time() ] ) : array

$timestamp is an optional parameter and defaults to the current timestamp. The function returns an array containing each time component. The following is an example of practical application:

// 输出当前日期时间数组
print_r(getdate());

// 输出 2021年4月20日 星期二
$date = getdate();
echo "{$date['year']}年{$date['mon']}月{$date['mday']}日 {$date['weekday']}";

The combination of strtotime and date

Due to the complementarity of the strtotime() and date() functions, in practical applications they are usually Use both together to convert a date string into the desired date format. The following is an example of practical application:

// 如果 $strDate 是 "2021-04-20"
$strDate = '2021-04-20';
$date = date('Y年m月d日',strtotime($strDate));
echo $date; // 输出 2021年04月20日

Summary

PHP time functions are very powerful and flexible. They can convert timestamps or date strings into various readable formats. Date time format. For developers, mastering PHP's time function can effectively improve development efficiency and code quality. As a final reminder, learn more about the usage and precautions of PHP time functions through PHP official documentation.

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