final_review

Lecture 27

Final Exam Review

13 Floréal, Year CCXXXI

Song of the day: Mr. Bojangles by Nina Simone (2011)

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Eeveelutionary Theory

As you may remember from the review, the Pokémon Eevee has several type-specific evolutions. Eevee will evolve into some of these Pokémon depending on which evolution stone it is given. For the purposes of this problem, we'll focus on the original three Eeveelutions:

• Vaporeon ("water"-type): If Eevee is given a Water Stone ("water_stone" in code).
• Jolteon ("electric"-type): If Eevee is given a Thunder Stone ("thunder_stone" in code).
• Flareon ("fire"-type): If Eevee is given a Fire Stone ("fire_stone" in code).

Define an Eevee class that will accept two parameters: nickname, a string containing the nickname given to the Eevee object, and description_filepath, a string containing the address of a txt file containing a short description of this specific Eevee object. The file, if it exists, will always look slightly different depending on the Eevee's specific stats, but it will always be of the following general format:

Eevee
Nature: friendly
Level: 5

The Eeevee class will have five instance attributes:

• nickname: The nickname passed by the user.
• evol_status: The current Eeveelutionary status of the Eevee object. The value of this attribute is None when the Eevee is un-evolved, or either "Vaporeon", "Jolteon", or "Flareon" if it has been evolved. We can assume that all newly instantiated Eevee objects start un-evolved.
• type: A string containing the current type of the Eevee object. We can assume that all newly instantiated Eevee objects are of type "normal".
• nature: A string containing the nature denoted in the file. Will be None if file is not successfully opened.
• level: An integer containing this object's level as denoted in the file. Will be 1 if file is not successfully opened.

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The Eevee class will have three instance methods associated to it. The first can_evolve() (sig: str => bool), will accept one string parameter, stone_name, a string containing the name of the evolutionary stone that the user wishes to give to this Eevee object. can_evolve() will then return True if and only if:

1. The Eevee object is un-evolved,
2. The stone_name is one of the three valid evolutionary stones mentioned above.

If either of these conditions is not met, can_evolve() will return False.

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Next, define a method called evolve() (sig: str => None). evolve() will accept one parameter, stone_name, a string containing the name of the evolutionary stone that the user wishes to give to this Eevee object. If the Eevee object meets all conditions necessary to evolve, evolve() will update the evol_status and type of the Eevee object to their appropriate new values.

To make this a little simpler, you may assume that the following dictionary is already defined at the top of your file, which you may use if you find it useful (in other words, you don't have to use it if you don't find it useful):

INFO_PER_STONE = {
    "water_stone": {
        # Water stone information
        "eeveelution": "Vaporeon",
        "type": "water"
    },
    "thunder_stone": {
        # Thunder stone information
        "eeveelution": "Jolteon",
        "type": "electric"
    },
    "fire_stone": {
        # Fire stone information
        "eeveelution": "Flareon",
        "type": "fire"
    }
}

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Finally, define a get_stats() method (sig: None => list) that will return a list of the values of all the object's non-None attributes. If you can, do this using list comprehension—only then will you become a Python deity.

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Sample behaviour:

# If the file exists...
camille = Eevee("Camille", "description.txt")
print(camille.get_stats())  # pre-evolution

camille.evolve("thunder_stone")
print(camille.get_stats())  # post-evolution

# If the file doesn't exist...
fryderyk = Eevee("Fryderyk", "not_description.txt")
print(fryderyk.get_stats())  # pre-evolution

fryderyk.evolve("fire_stone")
print(fryderyk.get_stats())  # post-evolution

Output:

['Camille', 'friendly', 5, 'normal']
['Camille', 'Jolteon', 'friendly', 5, 'electric']
['Fryderyk', 1, 'normal']
['Fryderyk', 'Flareon', 1, 'fire']

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Solution