AttributeError在我的python代码2中

Question

我在python中有以下代码行：

class BankAccount:
  def __init__ (self,balance = 0):
    self.balance = balance

    def deposit(self, deposit_amount= 30):
      self.deposit_amount=deposit_amount
      balance += deposit_amount
      return balance

      def withdraw (self,withdraw_amount= 10):
        if withdraw_amount > balance:
          raise RuntimeError('Invalid Transaction')
          balance -= withdraw_amount
          return balance

          class MinimumBalanceAccount(BankAccount):
            def __init__(self,balance = 0):
              self.balance = balance

              c = BankAccount()
              c.deposit(50)

它给了我这个错误：

AttributeError("BankAccount instance has no attribute 'deposit'"

Answer 1

如果您的缩进实际上是发布的，那么deposit函数是在__init__方法中定义的。因此，它不是类的属性，而只是__init__方法中可用的函数。下面的代码只是代码的副本，但是缩进是固定的：

class BankAccount:
    def __init__(self,balance=0):
        self.balance = balance

    def deposit(self, deposit_amount=30):
        self.deposit_amount=deposit_amount
        self.balance += deposit_amount
        return self.balance

    def withdraw(self,withdraw_amount=10):
        if withdraw_amount > self.balance:
            raise RuntimeError('Invalid Transaction')
        self.balance -= withdraw_amount
        return self.balance

class MinimumBalanceAccount(BankAccount):
    def __init__(self,balance = 0):
        self.balance = balance

c = BankAccount()
c.deposit(50)

这段代码适用于我，就像我用c = MinimumBalanceAccount()替换c = MinimumBalanceAccount()时一样。