PHP - Calendar jddayofweek() Function

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The PHP Calendar jddayofweek() function is used to find the day of the week for a given Julian Day. This function can return the day as an integer, a string, or a condensed string, depending on the format that is specified.

Syntax

Below is the syntax of the PHP Calendar jddayofweek() function −

int|string jddayofweek ( int $jd, int $mode = CAL_DOW_DAYNO )

Parameters

Below are the parameters of the jddayofweek() function −

• $jd − It is the julian day number as integer.

• $mode − It defines what to return (integer or string).

Mode values are as follows −

• 0 − The default. Returns the day number as an integer (0 = Sunday, 1 = Monday, etc.)

• 1 − Returns a string containing the day of the week (English-Gregorian).

• 2 − Returns a string with the shortened day of the week (English-Gregorian).

Return Value

The jddayofweek() function returns the day of the week using the format that the mode argument specifies. Can return a string or an integer depending on the mode.

PHP Version

First introduced in core PHP 4, the jddayofweek() function continues to function easily in PHP 5, PHP 7, and PHP 8.

Example 1

First we will show you the basic example of the PHP Calendar jddayofweek() function to get the day of the week for a given Julian Day as an integer.

<?php
   // Get the day of the week as an integer
   $julian_day = 2459215; // shows September 1, 2020
   
   $day = jddayofweek($julian_day, 0);
   
   echo "Day as integer: " . $day;
?>

Output

Here is the outcome of the following code −

Day as integer: 4

Example 2

This PHP example code shows you how to get the day of the week's complete name with the help of jddayofweek() function.

<?php
   // Get the day of the week
   $julian_day = 2459215; 
   
   $day = jddayofweek($julian_day, 1);
   
   echo "Day as full name: " . $day; 
?> 

Output

This will generate the below output −

Day as full name: Wednesday

Example 3

This example shows how you can retrieve the abbreviated name of the day of the week while using the jddayofweek() method of PHP.

Now the below code retrieves specific information from jddayofweek(), and prints it.

<?php
   // Get the day of the week 
   $julian_day = 2459215; 
  
   $day = jddayofweek($julian_day, 2);
   
   echo "Day as abbreviated name: " . $day; 
?> 

Output

This will create the below output −

Day as abbreviated name: Wed

Example 4

In the following example, we are using the jddayofweek() function to show flexibility of this function by finding out the Julian Day for a different day of the week.

<?php
   // Get the day of the week 
   $julian_day = 2451545; // shows January 1, 2000

   $day = jddayofweek($julian_day, 1);
   
   echo "Day for January 1, 2000: " . $day; 
?> 

Output

Following is the output of the above code −

Day for January 1, 2000: Saturday