如何在字典中包含来自类的实例列表？

Question

我创建了一个具有以下属性、方法和实例的自定义类：

class wizard:
  def __init__(self, first, last, pet, petname, patronus):
    self.first = first
    self.last = last
    self.pet = pet
    self.petname = petname
    self.patronus = patronus

  # Methods
  def fullname(self):
    return '{} {}'.format(wizard1.first, wizard1.last)

  def tell_pet(self):
    return '{} {}{} {} {} {}'.format(wizard1.first, wizard1.last,'\'s', wizard1.pet, 'is called', wizard1.petname)

  def expecto_patronum(self):
    return '{} {} {}'.format('A', wizard1.patronus, "appears!")


# Instances
harry = wizard('Harry', 'Potter', 'Owl', 'Hedwig', 'Stag')
ron = wizard('Ron', 'Weasley', 'Owl', 'Pigwidgeon', 'Dog')
hermione = wizard('Hermione', 'Granger', 'Cat', 'Crookshanks', 'Otter')
malfoy = wizard('Draco', 'Malfoy', 'Owl', 'Niffler', 'Dragon')

现在我想创建一个字典来存储类向导的实例。

hogwarts = {harry, ron, hermione, malfoy}

然而，作为输出，我得到的只是以下内容：

{<__main__.wizard object at 0x7fa2564d6898>, 
<__main__.wizard object at 0x7fa2564d61d0>, 
<__main__.wizard object at 0x7fa2564d6dd8>, 
<__main__.wizard object at 0x7fa2564bf7f0>}

相反，我希望字典能打印出存储在实例中的信息。我怎么能这么做？

Answer 1

您需要使用self来使用类属性。

class wizard:
  def __init__(self, first, last, pet, petname, patronus):
    self.first = first
    self.last = last
    self.pet = pet
    self.petname = petname
    self.patronus = patronus

  # Methods
  def fullname(self):
    return '{} {}'.format(self.first, self.last)

  def tell_pet(self):
    return '{} {}{} {} {} {}'.format(self.first, self.last,'\'s', self.pet, 'is called', self.petname)

  def expecto_patronum(self):
    return '{} {} {}'.format('A', self.patronus, "appears!")

你的字典实际上是一个set。您只需将实例放在一个list中，并遍历它以打印您认为合适的值，如下所示：

hogwarts = [harry, ron, hermione, malfoy]
for student in hogwarts:
    print('{}, {}, {}'.format(student.fullname(), student.tell_pet(), student.expecto_patronus()))

Answer 2

向类函数中添加表示形式。

def __repr__(self):
    print(f"First : {self.first }, Last : {self.last} ....")

Answer 3

您可以将__repr__或__str__方法放置在类中，并使其返回打印对象时要打印的内容。

一个例子是：

def __repr__(self):
    return f'I am {self.first} {self.last}. I have a pet {self.pet}, its name is {self.petname}. My patronus is {self.patronus}.'