Sets, Tuples, and Dictionaries

Solutions

Here's what you should have seen while working through the exercises.

Sets

Here's what you should have seen in your REPL:

>>> my_set = {}
>>> type(my_set)
<class 'dict'>
>>> my_set = set()
>>> type(my_set)
<class 'set'>

>>> my_set = {1, 2, 3}
>>> my_set.add(4)
>>> my_set.remove(2)
>>> 2 in my_set
False

>>> my_set
{1, 3, 4}
>>> my_set.add(3)
>>> my_set
{1, 3, 4}

>>> my_other_set = {1, 2, 3}
>>> my_set.union(my_other_set)
{1, 2, 3, 4}
>>> my_set.intersection(my_other_set)
{1, 3}

Tuples

Here's what you should have seen in your REPL:

>>> my_tuple = 1,
>>> my_tuple
(1,)
>>> my_tuple[1] = 2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment

>>> person = ('Jim', 29, 'Austin, TX')
>>> name, age, hometown = person
>>> name
'Jim'
>>> age
29
>>> hometown
'Austin, TX'

Dictionaries

Here's what you should have seen in your REPL:

>>> my_dict = {"key": "value"}
>>> my_dict[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 0

>>> my_dict["hello"] = "world"
>>> my_dict["foo"] = "bar"
>>> my_dict
{'key': 'value', 'hello': 'world', 'foo': 'bar'}

>>> my_dict["hello"]
'world'
>>> my_dict.get("hello")
'world'
>>> my_dict["baz"]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 'baz'
>>> "baz" in my_dict
False
>>> my_dict.get("baz", "default response")
'default response'

>>> my_dict.keys()
dict_keys(['key', 'hello', 'foo'])
>>> my_dict.values()
dict_values(['value', 'world', 'bar'])

>>> my_dict.items()
dict_items([('key', 'value'), ('hello', 'world'), ('foo', 'bar')])

Mutability

Here's what you should have seen in your REPL:

>>> my_list = [1, 2, 3]
>>> my_list[0] = 'a'
>>> my_list
['a', 2, 3]

>>> my_dict = {"hello": "world"}
>>> my_dict["foo"] = "bar"
>>> my_dict
{'hello': 'world', 'foo': 'bar'}

>>> my_set = {1, 2, 3}
>>> my_set[0] = 'a' # This will throw a TypeError
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'set' object does not support item assignment
>>> my_set.add('a')
>>> my_set
{1, 2, 3, 'a'}

>>> my_tuple = (1, 2, 3)
>>> my_tuple[0] = 'a' # This will throw a TypeError
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment