python - 为什么我的嵌套 python 类实例变成了元组？

Question

我这样定义了一些类:

class CustomParameter():
    def __init__(self, strFriendlyAttribName, strSystemAttribName):
        self.FriendlyAttribName = strFriendlyAttribName
        self.SystemAttribName = strSystemAttribName

class PartMaster():
    AttribNameList = ["Part Number", "Name", "Standard Part", "Part Type", "ControlledBy", "PIN", "Design Responsibility"]

    def __init__(self):
        self._UUID = None

        self.PartNumber = CustomParameter("Part Number", "V_ID"),
        self.Name = CustomParameter("Name", "V_name"),
        self.StandardPart = CustomParameter("Standard Part", "V508_isStandardPart"),
        self.PartType = CustomParameter("Part Type", "V511_PartType"),
        self.ControlledBy = CustomParameter("ControlledBy", "V511_ControlledBy"),
        self.PIN = CustomParameter("PIN", "BOECACPinItemNumber"),
        self.DesignResponsibility = CustomParameter("Design Responsibility", "BOECACDesignRpnse")

class Part():
    def __init__(self, PartNumber):

        self.PartNumber = PartNumber

        #This instance wraps
        self.PartMaster = PartMaster() #create new instance



test = Part("ABC")

我希望 test.PartMaster.PIN将是 CustomParameter 的一个实例，但它是一个元组 tuple: (<__main__.CustomParameter instance at 0x0000000002D724C8>,)为什么会这样，我怎样才能不这样？

我想构建我的类 test.PartMaster.PIN返回我的 CustomParameter 类的实例实例。有什么想法吗？

Answer 1

因为每当您的类初始化时，PartMaster 类的实例变量都在末尾设置了逗号:)

Python 对此进行解释:

x = 'test',

作为:

('test',)

试试这个:

def __init__(self):
    self._UUID = None

    self.PartNumber = CustomParameter("Part Number", "V_ID")
    self.Name = CustomParameter("Name", "V_name")
    self.StandardPart = CustomParameter("Standard Part", "V508_isStandardPart")
    self.PartType = CustomParameter("Part Type", "V511_PartType")
    self.ControlledBy = CustomParameter("ControlledBy", "V511_ControlledBy")
    self.PIN = CustomParameter("PIN", "BOECACPinItemNumber")

这在我身上发生过很多次。每当我从编写大量字典转向在类中设置变量时，我总是会忘记逗号。但是，将您的头发拉到上面一次，您将永远知道要寻找什么!