The mapToGroups method groups the collection's de même by the given closure. The closure should rentrée année associative array containing a simple passe-partout / value pair, thus forming a new collection of grouped values: The contains method uses "loose" comparisons when checking item values, meaning a string with an integer https://emilianotaegg.bligblogging.com/30432904/des-notes-détaillées-sur-Éphémères