12.2. Function Return¶

12.2.1. Syntax¶

def myfunction():
    return <expression>

>>> def mean():
...     return (1+2) / 2

>>> def add():
...     a = 1
...     b = 2
...     return a + b

12.2.2. Return Keyword¶

return keyword indicates outcome of the function
Code after return will not execute

>>> def hello():
...     return 'hello world'
>>>
>>>
>>> hello()
'hello world'

>>> def hello():
...     return 'hello world'
...     print('This will not be executed')
>>>
>>>
>>> hello()
'hello world'

12.2.3. Return Basic Type¶

>>> def myfunction():
...     return 42

>>> def myfunction():
...     return 13.37

>>> def myfunction():
...     return 'Mark Watney'

>>> def myfunction():
...     return True

12.2.4. Return Sequence¶

>>> def myfunction():
...     return list([42, 13.37, 'Mark Watney'])

>>> def myfunction():
...     return [42, 13.37, 'Mark Watney']

>>> def myfunction():
...     return tuple((42, 13.37, 'Mark Watney'))

>>> def myfunction():
...     return (42, 13.37, 'Mark Watney')

>>> def myfunction():
...     return 42, 13.37, 'Mark Watney'

>>> def myfunction():
...     return set({42, 13.37, 'Mark Watney'})

>>> def myfunction():
...     return {42, 13.37, 'Mark Watney'}

>>> def myfunction():
...     return frozenset({42, 13.37, 'Mark Watney'})

12.2.5. Return Mapping¶

>>> def myfunction():
...     return dict(firstname='Mark', lastname='Watney')

>>> def myfunction():
...     return {'firstname': 'Mark', 'lastname': 'Watney'}

12.2.6. Return Nested Sequence¶

>>> def myfunction():
...     return [('Mark', 'Watney'),
...             {'Jan Twardowski', 'Melissa Lewis'},
...             {'astro': 'Иван Иванович', 'agency': {'name': 'Roscosmos'}},
...             {'astro': 'Jiménez', 'missions': ('Mercury', 'Gemini')},
...             {'astro': 'Vogel', 'missions': (list(), tuple(), set())}]

12.2.7. Return None¶

Python will return None if no explicit return is specified

>>> def myfunction():
...     return None

>>> def myfunction():
...     print('hello')

>>> def myfunction():
...     pass

>>> def myfunction():
...     """My function"""

12.2.8. Intercept returned value¶

>>> def myfunction():
...     return 1
>>>
>>>
>>> result = myfunction()
>>> print(result)
1

12.2.9. Assignments¶

Code 12.2. Solution¶

"""
* Assignment: Function Return Numbers
* Required: yes
* Complexity: easy
* Lines of code: 3 lines
* Time: 3 min

English:
    1. Define function `compute` without parameters
    2. Function should return sum of `1` and `2`
    3. Define `result` with result of function call
    4. Run doctests - all must succeed

Polish:
    1. Zdefiniuj funkcję `compute` bez parametrów
    2. Funkcja powinna zwracać sumę `1` i `2`
    3. Zdefiniuj `result` z wynikiem wywołania funkcji
    4. Uruchom doctesty - wszystkie muszą się powieść

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from inspect import isfunction

    >>> isfunction(compute)
    True
    >>> result
    3
"""