date formatting code snippets in swift

format a date in to the format 'yyyy-mm-dd hh:mm:ss' in swift

format a date in to the format 'yyyy-mm-dd hh:mm:ss.fff' in swift

format a date in to the format month day, year hour:minute:second am/pm in swift

format a date in to the format month day, year hour:minute:second.fff am/pm zzz in swift