Python 写一个银行系统实现是一个用于模拟银行基本功能的程序，如开户、销户、查询余额、转账、取款、存款等

创建一个简单的银行系统模拟程序，通常会使用 Python 的面向对象编程（OOP）特性，尤其是类和方法来定义账户、客户和银行操作。以下是一个基础的示例，展示了如何实现这样的系统：

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

    def deposit(self, amount):
        self.balance += amount
        print(f"存入了 {amount} 元，当前余额为 {self.balance} 元.")

    def withdraw(self, amount):
        if amount <= self.balance:
            self.balance -= amount
            print(f"取出了 {amount} 元，当前余额为 {self.balance} 元.")
        else:
            print("余额不足，请检查！")

    def check_balance(self):
        return self.balance

class Customer:
    def __init__(self, name, accounts=None):
        self.name = name
        if accounts is None:
            self.accounts = [BankAccount()]
        else:
            self.accounts = accounts

    def open_account(self, initial_deposit=0):
        new_account = BankAccount(len(self.accounts) + 1, initial_deposit)
        self.accounts.append(new_account)
        return new_account

    def close_account(self, account_number):
        for acc in self.accounts:
            if acc.account_number == account_number:
                self.accounts.remove(acc)
                print(f"{self.name}关闭了账户{account_number}.")
                break

    def transfer(self, from_account, to_account, amount):
        if from_account.check_balance() >= amount:
            from_account.withdraw(amount)
            to_account.deposit(amount)
            print(f"{self.name}从{from_account.account_number}转出{amount}元到{to_account.account_number}.")
        else:
            print("转账金额超过余额！")

# 使用示例
customer = Customer("张三")
account1 = customer.open_account(1000)
account2 = customer.open_account()

customer.transfer(account1, account2, 500)

# 客户可以调用各个账户的方法进行操作
account1.check_balance()
account2.withdraw(200)