Solving a Character printing program using data class-CodePudding

I'm having problems with a program. It's a program using a data class to print out movie characters. However I don't have a lot of practice with data classes and don't really know how to use them. So I'm wondering if someone could help me solve this problem?

This is the main

import Character 


#  Creates a character called Indiana
   Indiana = Character.Character('Indiana', 'Human', 'Earth')
   print(Indiana.to_string())

#  Creates an empty character later filled with Luke Skywalker
   luke = Character.Character()
   luke.set_name('Luke Skywalker')
   luke.set_kind('Human')
   luke.set_planet('Tatooine')
   print(luke.to_string())

I haven't really gotten too far with the data class, so far I've only come up with this

from dataclasses import dataclass

@dataclass
class Character:
   name: str
   kind: str
   planet: str

def char(name,kind,planet):
   set_name = name
   set_kind = kind
   set_planet = planet

and the output should be like this

Output:

Indiana is a(n) Human from Earth

Luke Skywalker is a(n) Human from Tatooine

I hope someone can help me!

CodePudding user response：

Dataclasses automatically create constructors, setters, getters, and string conversion methods as appropriate to the options on the @dataclass decorator and the class attributes you define in the body of the class. Delete your char function and do:

from Character import Character  

#  Creates a character called Indiana
indiana = Character('Indiana', 'Human', 'Earth')
print(indiana)

#  Creates an empty character later filled with Luke Skywalker
luke = Character('', '', '')
luke.name = 'Luke Skywalker'
luke.kind = 'Human'
luke.planet = 'Tatooine'
print(luke)

This prints:

Character(name='Indiana', kind='Human', planet='Earth')
Character(name='Luke Skywalker', kind='Human', planet='Tatooine')

If you want your Character's fields to have default values, set them in the Character class like this:

@dataclass
class Character:
    name: str = ''
    kind: str = ''
    planet: str = ''

and now you can do luke = Character() and it will fill in the three '' empty strings for you automatically.

If you want to change the way that a Character is converted to a string, add a __str__ method, e.g.:

@dataclass
class Character:
    name: str = ''
    kind: str = ''
    planet: str = ''

    def __str__(self) -> str:
        return f"{self.name}, a {self.kind} from {self.planet}"

Note that in Python you don't have to explicitly call a method like to_string to print an object as a string; the print function will automatically convert its arguments to strings with the str() function, which in turn will call the __str__ method of the object to do the conversion.

CodePudding user response：

You should be getting an error when you try to instantiate empty character.. You can avoid that by specifying default value .. To print, you can override str method see below

from dataclasses import dataclass

@dataclass

class Character:

    name:str=None
    kind:str=None
    planet:str=None

    def set_char(self,name,kind,planet):
            self.name=name
            self.kind=kind
            self.planet=planet

    def __str__(self):
            return f'{self.name} is a(n) {self.kind} from {self.planet}'

Indiana=Character('Indiana','Human','Earth') print(Indiana) Luke=Character() Luke.set_char('Luke SkyWalker','Human','Tatooine') print(Luke)