Python Enums Exercises With Answers

What is Color.RED?

1. The string red
2. A class
3. A dictionary
4. An enum membercorrect

Answer: An enum member

Why: Enum members are unique objects; the string is stored in .value.

What does this code print?

from enum import Enum
class Color(Enum):
    RED = "red"
print(Color.RED.value)

1. RED
2. redcorrect
3. None
4. Color.RED

Answer: red

Why: The value attribute returns the underlying string.

What does iterating over an Enum yield?

1. Only its names
2. Its memberscorrect
3. Integer indexes
4. Only its values

Answer: Its members

Why: Iteration yields the member objects in definition order.

What does Color('green') return?

1. A new enum class
2. ValueError
3. The string green
4. The Color.GREEN membercorrect

Answer: The Color.GREEN member

Why: Calling the enum with a value looks up the matching member.

Complete the base class for an enum.

from enum import Enum
class Color(____):
    RED = "red"

Answer: Enum

Why: Enum is the standard base class for named members.

Complete the attribute that returns the underlying value.

from enum import Enum
class Color(Enum):
    RED = "red"
print(Color.RED.____)

Answer: value

Why: A member stores its assigned value in .value.

Complete the attribute that returns the member name.

from enum import Enum
class Color(Enum):
    RED = "red"
print(Color.RED.____)

Answer: name

Why: A member stores its identifier in .name.

Complete the name lookup.

from enum import Enum
class Color(Enum):
    RED = "red"
print(Color["____"])

Answer: RED

Why: Square brackets look up a member by its name.

What does the program output?

from enum import Enum
class Color(Enum):
    RED = "red"
print(Color.RED.name)

Answer: RED

Why: The name attribute is the identifier RED.

What appears on the screen?

from enum import Enum
class Color(Enum):
    RED = "red"
    GREEN = "green"
print(Color("green").value)

Answer: green

Why: Lookup by value returns GREEN, whose value is green.

What is printed?

from enum import Enum
class Color(Enum):
    RED = "red"
    GREEN = "green"
print(len(list(Color)))

Answer: 2

Why: There are two members, so the list has length two.

What is the output?

from enum import Enum
class Color(Enum):
    RED = "red"
print(Color.RED is Color.RED)

Answer: True

Why: Enum members are singletons, so the identity comparison is true.