Python - 缺少位置参数

Question

我的Python代码包含以下类

class payment_calculations:
    def __init__(self):
        self.__interestdatecurrent = str()
        return None

    def paymentfixed(self, notional, datecouponstart, datecouponend, interestratecurrent, interestratefixed, datecurrent):

当我用

打电话时

fixedpayment = payment_calculations.paymentfixed(interestnotional, datecoupon1, datecoupon2, c, interestratefixed, interestdatecurrent)

我看到以下堆栈跟踪

 File "C:\Python34\mod_payment_calculation.py", line 83, in coupondatesfixed
    fixedpayment = payment_calculations.paymentfixed(interestnotional,datecoupon1,datecoupon2,c,interestratefixed,interestdatecurrent)
TypeError: paymentfixed() missing 1 required positional argument: 'datecurrent'

我从测试文件调用时已经确认这是有效的。但是，当我从模块本身内部运行时，它会失败。有什么想法吗？

Answer 1

您需要创建该类的实例：

pc = payment_calculations()
fixedpayment = pc.paymentfixed(interestnotional, datecoupon1, datecoupon2, c, interestratefixed, interestdatecurrent)

否则您正在调用未绑定的函数，并且不会自动提供self参数。相反，interestnotional值转到self参数，datecoupon1转换为notational参数等等。