path_extension_of(an_item)

Obtain a path extension of the item. The result does not starts with ".".

missing value will be returned, if the target item does not have a path extension.

• an_item (a reference to file/folder) : Almost types of references to a file or a folder can be accepted. e.g.) HFS path, POSIX path, alias, file specification, reference form of Finder and furl.

text : A path extension