PHP DateTimeImmutable - setISODate() Method

The PHP DateTimeImmutable::setISODate() method returns a DateTimeImmutable object with date set to the specified date, according to the ISO 8601 standard - using weeks and day offsets rather than specific dates.

Syntax

public DateTimeImmutable::setISODate(year, week, dayOfWeek)

Parameters

`year`	`Required.` Specify an integer value representing year of the date.
`week`	`Required.` Specify an integer value representing week of the date.
`dayOfWeek`	`Optional.` Specify an integer value representing the day of the week. Default is 1.

Return Value

Returns a new DateTimeImmutable object with date set to the specified date on success, otherwise returns false.

Example: Sets the date

The example below shows the usage of DateTimeImmutable::setISODate() method.

<?php
  //datetime string
  $datetime_string = "14-May-2015";

  //creating a DateTimeImmutable object
  $date = new DateTimeImmutable($datetime_string);

  //creating a new DateTimeImmutable object 
  //with date set to new value
  $date_new = $date->setISODate(2016, 10, 4); 

  //formatting the datetime to print it
  echo "Original date: ".$date->format("d-M-Y")."\n";
  echo "New date:      ".$date_new->format("d-M-Y")."\n";
?>

The output of the above code will be:

Original date: 14-May-2015
New date:      10-Mar-2016

Example: Adding values exceeding ranges

When values exceeding ranges are passed to this method, they will be added to their parent values. Consider the example below:

<?php
  //creating a DateTimeImmutable object
  $date = new DateTimeImmutable();

  //setting date to a new value
  $date_new = $date->setISODate(2001, 10, 2);
  echo $date_new->format('d-M-Y') . "\n";

  //setting date with exceeding range of dayOfWeek -
  //exceeding days (2 days) will be added 
  $date_new = $date->setISODate(2001, 10, 9);
  echo $date_new->format('d-M-Y') . "\n";

  //setting date with exceeding range of week -
  //exceeding weeks (3 weeks) will be added
  $date_new = $date->setISODate(2001, 55, 2);
  echo $date_new->format('d-M-Y') . "\n";
?>

The output of the above code will be:

06-Mar-2001
13-Mar-2001
15-Jan-2002

Example: Finding the month a week is in

The example below illustrates on finding the month a week is in.

<?php
  //creating a DateTimeImmutable object
  $date = new DateTimeImmutable();

  //setting date to a new value
  $date_new = $date->setISODate(2001, 10);

  //finding the month the week is in
  echo $date_new->format('n') . "\n";
?>

The output of the above code will be:

❮ PHP Date and Time Reference