Swift - 将日期字符串从“datepicker填充日期字段”转换为nsdate

Ive got a UIDatepicker attached to a text field named dateField. when the user clicks on the field, a UIDatePicker pops up and the user chooses a date of birth. That date is saved as a string to that dateField and shows up formatted according to the users location ie May 4 1990 in USA or 4 May 1990 in Australia.Ive got a UIDatepicker attached to a text field