AngleFormat currently formats the degrees, minutes and seconds field unconditionally. We should be able to omit the fields having a zero value, if desired, for more compact representation. Optional field can be identified by a question mark in the pattern. For example the 90° value:
- Using DD°MM′SS″ pattern, is always formatted as 90°00′00″.
- Using DD°?MM′?SS″? pattern, is formatted as 90° since the minutes and seconds fields are zero.
The use of question mark is by analogy with regular expression, where ? means "zero or one occurrence of previous character".