Since the return statement in getName
specifies multiple elements:
def getName(self):
return self.first_name, self.last_name
Python will return a container object that basically contains them.
In this case, returning a comma separated set of elements creates a tuple. Multiple values can only be returned inside containers.
Let's use a simpler function that returns multiple values:
def foo(a, b):
return a, b
You can look at the byte code generated by using dis.dis
, a disassembler for Python bytecode. For comma separated values w/o any brackets, it looks like this:
>>> import dis
>>> def foo(a, b):
... return a,b
>>> dis.dis(foo)
2 0 LOAD_FAST 0 (a)
3 LOAD_FAST 1 (b)
6 BUILD_TUPLE 2
9 RETURN_VALUE
As you can see the values are first loaded on the internal stack with LOAD_FAST
and then a BUILD_TUPLE
(grabbing the previous 2
elements placed on the stack) is generated. Python knows to create a tuple due to the commas being present.
You could alternatively specify another return type, for example a list, by using []
. For this case, a BUILD_LIST
is going to be issued following the same semantics as it's tuple equivalent:
>>> def foo_list(a, b):
... return [a, b]
>>> dis.dis(foo_list)
2 0 LOAD_FAST 0 (a)
3 LOAD_FAST 1 (b)
6 BUILD_LIST 2
9 RETURN_VALUE
The type of object returned really depends on the presence of brackets (for tuples ()
can be omitted if there's at least one comma). []
creates lists and {}
sets. Dictionaries need key:val
pairs.
To summarize, one actual object is returned. If that object is of a container type, it can contain multiple values giving the impression of multiple results returned. The usual method then is to unpack them directly:
>>> first_name, last_name = f.getName()
>>> print (first_name, last_name)
As an aside to all this, your Java ways are leaking into Python :-)
Don't use getters when writing classes in Python, use properties
. Properties are the idiomatic way to manage attributes, for more on these, see a nice answer here.