How to get the first day of the current year?

In PHP, you can use the mktime function to get the Unix timestamp of the first day of the current year, then use the date function to format it as a date string.

Here's an example:

<?php

$firstDayOfYear = mktime(0, 0, 0, 1, 1, date("Y"));
$firstDayOfYear = date("Y-m-d", $firstDayOfYear);

echo $firstDayOfYear;

The mktime function creates a timestamp based on the parameters provided: hour (0), minute (0), second (0), month (1, January), day (1), and year (the current year, obtained using the date function with the format "Y").

The date function then formats the timestamp as a date string in the format "Y-m-d".