 date api functions preconfigured arrays both translated and untranslated values are available the dateweekdaysordered function will shift an array of week day names so it starts with the site s first day of the week otherwise the weekday names start with sunday as the first value the expected order for many php and sql functions datemonthnames datemonthnamesabbr datemonthnamesuntranslated dateweekdays dateweekdaysabbr dateweekdaysuntranslated dateweekdaysordered dateyears datehours dateminutes dateseconds datetimezonenames dateampm  miscellaneous date manipulation functions predefined constants and functions that will handle pre1970 and post2038 dates in both php 4 and php 5 in any os dates can be converted from one type to another and date parts can be extracted from any date type datedatetime dateiso dateunix datearray dateobject dateical dateconvert dateisvalid datepartisvalid datepartextract  date calculation and navigation datediff will find the time difference between any two days measured in seconds minutes hours days months weeks or years datedaysinmonth datedaysinyear dateweeksinyear datelastdayofmonth datedayofweek datedayofweekname datediff  date regex and format helpers predefined constants an array of date format strings and their equivalent regex strings dateregexloose is a very loose regex that will pull date parts out of an iso date with or without separators using either t or a space to separate date and time and with or without time dateformatdate is similar to formatdate except it takes a date object instead of a timestamp as the first parameter dateformatiso dateformatdatetime dateformatunix dateformatical dateregexiso dateregexdatetime dateregexloose dateformatdate datet dateshortformats datemediumformats datelongformats dateformatpatterns  