Example obtaining a week and its boundaries (for building a calendar view):<?php$date = new DateTime('now');$locale = 'en_US';$thisWeek = IntlCalendar::fromDateTime($date, $locale);$thisWeek->set(IntlCalendar::FIELD_DAY_OF_WEEK, $thisWeek->getFirstDayOfWeek());$weekStart = $thisWeek->toDateTime();$daysToAdvance = $thisWeek->getMaximum(IntlCalendar::FIELD_DAY_OF_WEEK) - 1;$weekEnd = $weekStart->modify("+{$daysToAdvance} days");$previousWeek = IntlCalendar::fromDateTime($date, $locale);$previousWeek->add(IntlCalendar::FIELD_WEEK_OF_YEAR, -1);$previousWeek = $previousWeek->toDateTime();$nextWeek = IntlCalendar::fromDateTime($date, $locale);$nextWeek->add(IntlCalendar::FIELD_WEEK_OF_YEAR, 1);$nextWeek = $nextWeek->toDateTime();?>