PHP | IntlCalendar setFirstDayOfWeek() Function

The IntlCalendar::setFirstDayOfWeek() function is an inbuilt function in PHP which is used to set the day on which the week is to be started. This function affects the behaviors of fields that depend on the week such as IntlCalendar::FIELD_WEEK_OF_YEAR and IntlCalendar::FIELD_YEAR_WOY.

Syntax:

• Object oriented style

  bool IntlCalendar::setFirstDayOfWeek( int $dayOfWeek )

• Procedural style

  bool intlcal_set_first_day_of_week( IntlCalendar $cal, int $dayOfWeek )

Parameters: This function uses two parameters as mentioned above and described below:

• $cal: This parameter holds the resource of IntlCalendar object.
• $dayOfWeek: This parameter holds one of the field constants such as IntlCalendar::DOW_SUNDAY, IntlCalendar::DOW_MONDAY, …, IntlCalendar::DOW_SATURDAY.

Return Value: This function returns True on success and False in case of invalid parameters.

Below program illustrates the IntlCalendar::setFirstDayOfWeek() function in PHP:

Program:

<?php

// Set the DateTime zone
ini_set('date.timezone', 'Asia/Calcutta');
ini_set('intl.default_locale', 'es_ES');

// Create an instance of IntlCalendar
$calendar = IntlCalendar::createInstance('Asia/Calcutta');

// Set the DateTime to the calendar object
$calendar->set(2019, 8, 25);

// Get first day of the week
var_dump($calendar->getFirstDayOfWeek());

// Set first day of the week
$calendar->setFirstDayOfWeek(IntlCalendar::DOW_SUNDAY);

// Get first day of the week
var_dump($calendar->getFirstDayOfWeek());

?>

Output:

int(2)
int(1)

Reference: https://www.php.net/manual/en/intlcalendar.setfirstdayofweek.php