PHP - Calendar jdtofrench() Function

---

---

The PHP Calendar jdtofrench() function is used to convert a Julian Day Count to the French Republican Calendar. Its opposite to FrenchToJD function.

France used the French Republican calendar from 1793 to 1805. The function helps to translate Julian dates into this historical calendar system.

Syntax

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

string jdtofrench (int $jd)

Parameters

This function accepts $jd parameter which is an integer is used to denote the error code. This error code is returned by a Calendar multi function like Calendar_multi_exec().

Return Value

The jdtofrench() function returns french revolution date as a string in the form "month/day/year".

PHP Version

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

Example 1

Here is the basic example of the PHP Calendar jdtofrench() function to convert a static Julian Day Count to the French calendar.

<?php
   // Static Julian Day Count
   $jd = 2378493; 
   $fd = jdtofrench($jd);
   echo "Julian Day $jd is $fd in French calendar.";   
?>

Output

Here is the outcome of the following code −

Julian Day 2378493 is 4/7/8 in French calendar.

Example 2

In the below PHP code we will try to use the jdtofrench() function and convert a Julian Day from a date string to the French calendar date.

<?php
   // A date within the French calendar period
   $date_string = '1793-09-22'; 
   
   $jd = gregoriantojd(date('n', strtotime($date_string)), date('j', strtotime($date_string)), date('Y', strtotime($date_string)));
   $fd = jdtofrench($jd);
   
   echo "The French date for $date_string is $fd.";
?> 

Output

This will generate the below output −

The French date for 1793-09-22 is 1/1/2.

Example 3

This example shows how to use a variable to save the Julian Day, which is then converted to the French Revolutionary Calendar using the jdtofrench() function.

<?php
   // A valid Julian Day Number in the French calendar
   $jd = 2378493; 
   $fd = jdtofrench($jd);

   echo "The date for Julian Day $jd is $fd.";
?> 

Output

This will create the below output −

The date for Julian Day 2378493 is 4/7/8.

Example 4

In the following example, we are using the jdtofrench() function to calculate the Julian Day of a previous date and convert it to the French calendar.

<?php
   // Past date
   $date = '1800-01-01';
   $jd = gregoriantojd(date('n', strtotime($date)), date('j', strtotime($date)), date('Y', strtotime($date)));
   $fd = jdtofrench($jd);
   echo "The French date for $date is $fd.";
?> 

Output

Following is the output of the above code −

The French date for 1800-01-01 is 4/11/8.