All functions return a value when called.
If a return statement is followed by an expression list, that expression list is evaluated and the value is returned:
>>> def greater_than_1(n):
... return n > 1
...
>>> print(greater_than_1(1))
False
>>> print(greater_than_1(2))
True
If no expression list is specified, None is returned:
>>> def no_expression_list():
... return # No return expression list.
...
>>> print(no_expression_list())
None
If a return statement is reached during the execution of a function, the current function call is left at that point:
>>> def return_middle():
... a = 1
... return a
... a = 2 # This assignment is never reached.
...
>>> print(return_middle())
1
If there is no return statement the function returns None when it reaches the end:
>>> def no_return():
... pass # No return statement.
...
>>> print(no_return())
None
A single function can have multiple return statements. Execution of the function ends when one of these return statements is reached:
>>> def multiple_returns(n):
... if(n):
... return "First Return Statement"
... else:
... return "Second Return Statement"
...
>>> print(multiple_returns(True))
First Return Statement
>>> print(multiple_returns(False))
Second Return Statement
A single function can return various types:
>>> def various_return_types(n):
... if(n==1):
... return "Hello World." # Return a string
... elif(n==2):
... return 42 # Return a value
... else:
... return True # Return a boolean
...
>>> print(various_return_types(1))
Hello World.
>>> print(various_return_types(2))
42
>>> print(various_return_types(3))
True
It is even possible to have a single function return multiple values with only a single return:
>>> def return_two_values():
... a = 40
... b = 2
... return a,b
...
>>> print("First value = %d, Second value = %d" %(return_two_values()))
First value = 40, Second value = 2