Conditionals & Tuples

Question 1

What is a ‘tuple’ in Python?

Answer 1

An immutable sequence of comma-separated immutable objects enclosed in (parenthesis)
>>> a = ('a', 123, [4,5,6])
>>> a[0]
'a'
>>> a[0:2]
('a', 123)

Question 2

What are the three main places where we will use tuples?

Answer 2

1. As keys to dictionaries;
2. Passing/returning multiple values to functions
3. In assignments

Question 3

Give an example of using tuples in assignments.

Answer 3

>>> a = 1; b = 2
>>> print(a, b)
(1, 2)
>>> (a, b) = (b, a)
>>> print(a, b)
(2, 1)

Question 4

What is the function we use to cast an object to a Boolean?

Answer 4

bool(obj)

Question 5

True or false: every type has a unique value for which bool() evaluates to False.

Answer 5

True

Question 6

Which integer will evaluate to False when cast to bool(int)?

Answer 6

> > > bool(0)

False

Question 7

Which string will evaluate to False when cast to bool(str)?

Answer 7

> > > bool(“”) # empty string

False

Question 8

Which float will evaluate to False when cast to bool(float)?

Answer 8

> > > bool(0.0)

False

Question 9

Which tuple will evaluate to False when cast to bool(tuple)?

Answer 9

> > > bool(()) # empty tuple

False

Question 10

Which list will evaluate to False when cast to bool(list)?

Answer 10

> > > bool([]) # empty list

False

Question 11

Which dictionary will evaluate to False when cast to bool(dict)?

Answer 11

> > > bool({}) # empty dict

False