Functions

Question 1

To define a Python function, you type ____, the function name, parentheses enclosing any input parameters to the function, and then finally, a _____

Answer 1

def, colon

Question 2

Creating a function that returns a value

Answer 2

> > > def agree():
… return True
…

Question 3

Example of passing in parameter

Answer 3

> > > def echo(anything):
… return anything + ‘ ‘ + anything

Question 4

______ is a special Python value that holds a place when there is nothing to say. It is not the same as the boolean value False, although it looks false when evaluated as a boolean.

Answer 4

None
»> thing = None
»> if thing:
… print(“It’s some thing”)
… else:
… print(“It’s no thing”)

Question 5

To distinguish None from a boolean False value, use Python’s ____ operator

Answer 5

is
»> thing = None
»> if thing is None:
… print(“It’s nothing”)
… else:
… print(“It’s something”)
…
It’s nothing

Question 6

To avoid positional argument confusion, you can specify arguments by the names of their corresponding parameters, even in a different order from their definition in the function:

Answer 6

> > > menu(entree=’beef’, dessert=’bagel’, wine=’bordeaux’)
{‘wine’: ‘bordeaux’, ‘entree’: ‘beef’, ‘dessert’: ‘bagel’}

Question 7

You can specify _____ values for parameters. The default is used if the caller does not provide a corresponding argument.

Answer 7

default
»> def menu(wine, entree, dessert=’pudding’):
… return {‘wine’: wine, ‘entree’: entree, ‘dessert’: dessert}

Question 8

When used inside the function with a parameter, an asterisk groups a variable number of positional arguments into a ____ _____ of parameter values

Answer 8

single tuple

Question 9

Example of positional arguments with *

Answer 9

> > > def print_args(*args):
… print(‘Positional tuple:’, args)
‘
print_args(3, 2, 1, ‘wait!’, ‘uh…’)
Positional tuple: (3, 2, 1, ‘wait!’, ‘uh…’)

Question 10

You can use two asterisks (**) to group keyword arguments into a ______, where the argument names are the keys, and their values are the corresponding dictionary values.

Answer 10

dictionary
»> def print_kwargs(**kwargs):
… print(‘Keyword arguments:’, kwargs)

Question 11

If an argument is _____, its value can be changed from inside the function via its corresponding parameter

Answer 11

mutable

Question 12

You can use _____ as elements of lists, tuples, sets, and dictionaries. ______ are immutable, so you can also use them as dictionary keys

Answer 12

functions

Question 13

You can define a function within another function

Answer 13

True
»> def outer(a, b):
… def inner(c, d):
… return c + d
… return inner(a, b)

Question 14

A Python ______ function is an anonymous function expressed as a single statement. You can use it instead of a normal tiny function.

Answer 14

lambda

Question 15

Can you pass in functions as parameters in python?

Answer 15

Yes

Question 16

> > > def enliven(word): # give that prose more punch
… return word.capitalize() + ‘!’

Mixing our ingredients:
»> edit_story(stairs, enliven)
Thud!

Since enlviven function is so short, what can we do instead?

Answer 16

> > > edit_story(stairs, lambda word: word.capitalize() + ‘!’)
Thud!
Meow!
Thud!
Hiss!

Question 17

List of python tricks

Answer 17

*args and **kwargs
*Inner functions
*Functions as arguments

Question 18

The main part of a program defines the ____ ______; thus, the variables in that namespace are global variables.

Answer 18

global namespace

Question 19

To access the global variable rather than the local one within a function, you need to be explicit and use the _____ keyword

Answer 19

global

Question 20

To write empty functions in Python, we use ____ statement. ____ is a special statement that does nothing. It only works as a dummy statement.

Answer 20

pass