Three ways to get the day of the week based on time in php

PHP is a very popular server-side scripting language. It has a powerful and rich function library, which contains many functions for date and time operations. In many applications, we need to get the corresponding day of the week based on date or time, such as calendars, class schedules, etc. Here are some PHP methods for getting the day of the week based on time.

Use the date function directly

In PHP, we can use a built-in function date to get the day of the week of the current time. We only need to pass in the "w" parameter in a formatted string, which represents the day of the week. The returned result is a number between 0 and 6, with 0 representing Sunday and 1 ~ 6 representing Monday to Saturday.

The sample code is as follows:

$week = date("w");
echo $week; //输出结果：2（表示星期三）

The above code will get the day of the week of the current date and assign the result to the $week variable. The final output result is 2, which represents Wednesday.

If we want to convert the output result into the Chinese day of the week, we can add an array to correspond.

The sample code is as follows:

$week_array = array("日", "一", "二", "三", "四", "五", "六");
$week = date("w");
echo "今天是星期".$week_array[$week];

The above code will get the day of the week of the current date and output the corresponding Chinese day of the week to the screen, for example: today is Wednesday.

Use strtotime function

There is also a commonly used function in PHP is strtotime, which can convert a string into a timestamp. We can first convert the current time into a timestamp, and then use date Function gets the day of the week.

The sample code is as follows:

$week_array = array("日", "一", "二", "三", "四", "五", "六");
$week = date("w", strtotime("now"));
echo "今天是星期".$week_array[$week];

In the above code, strtotime("now") will return the timestamp of the current time, and $timestamp in date("w", $timestamp) will is to convert the timestamp into a number of the day of the week, and the final output result is: today is Wednesday.

Custom function

If we need to get the day of the week frequently, we can encapsulate a custom function for easy calling. The sample code is as follows:

function get_week_day($time){
    $week_array = array("日", "一", "二", "三", "四", "五", "六");
    $week = date("w", strtotime($time));
    return "星期".$week_array[$week];
}

$time = "2021-09-15";
echo get_week_day($time);

In the above code, we define a function named get_week_day. The passed-in parameter is a time string (for example: "2021-09-15"). The function first converts the Convert the string into a timestamp, then get the day of the week (Chinese day of the week) at that time, and finally return the result. The last line calls the function and the output is: Wednesday.

Summary:

For PHP developers, getting the day of the week based on time is a common development task. This article introduces three implementation methods: directly using the date function, using the strtotime function and custom functions. Among them, custom functions are more reusable and can improve the readability and maintainability of the code. Hope this article is helpful to everyone.

The above is the detailed content of Three ways to get the day of the week based on time in php. For more information, please follow other related articles on the PHP Chinese website!