Python in a Nutshell

Name

getargspec, formatargspec

Synopsis

getargspec(f)

f is a function object. getargspec returns a tuple with four items ( arg_names, extra_args, extra_kwds, arg_defaults ). arg_names is the sequence of names of f’s formal arguments. extra_args is the name of the special formal argument of the form * args, or None if f has no such special argument. extra_kwds is the name of the special formal argument of the form ** kwds, or None if f has no such special argument. arg_defaults is the tuple of default values for f’s arguments. You can deduce other details about f’s signature from getargspec’s results. For example, f has len( arg_names )-len( arg_defaults ) mandatory arguments, and the names of f’s optional arguments are the strings that are the items of the list slice arg_names [-len( arg_defaults ):].

formatargspec accepts one to four arguments that are the same as the items of the tuple that getargspec returns, and returns a formatted string that displays this information. Thus, formatargspec(*getargspec( f )) returns a formatted string with f’s formal arguments (i.e., f’s signature) in parentheses, as used in the def statement that created f.