Question

我在棋盘游戏Battleship上做了一个项目。因为0,1,2,3 ...是1,2,3,4 ......（我不知道该怎么称呼它），我需要变量行和列比它们小一点，即：

row -= 1
column -= 1

我需要在一堆函数中使用它，所以我认为如果我每次只有一个辅助函数它会更整洁。我尝试过这两种方法：

row, column = row -= 1, column -= 1

但是，这给我column -= 1上的语法错误。

我也尝试过：

def decimal_helper(row, column):
    row -= 1
    column -= 1
    return row, column

但是，这只会返回一个元组，而我需要单独返回两个变量。

Answer 1

row, column = row - 1, column - 1

你也可以采用更优雅的方式，并使用@jonrsharpe建议的单行：

    An exception of type 'System.IO.IOException' occurred in Npgsql.dll but was not handled in user code

    Additional information: TlsClientStream.ClientAlertException: CertificateExpired

   at TlsClientStream.TlsClientStream.SendAlertFatal(AlertDescription description, String message)

   at TlsClientStream.TlsClientStream.ParseCertificateMessage(Byte[] buf, Int32& pos)

   at TlsClientStream.TlsClientStream.TraverseHandshakeMessages()

   at TlsClientStream.TlsClientStream.GetInitialHandshakeMessages(Boolean allowApplicationData)

   at TlsClientStream.TlsClientStream.PerformInitialHandshake(String hostName, X509CertificateCollection clientCertificates, RemoteCertificateValidationCallback remoteCertificateValidationCallback, Boolean checkCertificateRevocation)

Answer 2

我发现这更优雅。这样就封装了“转换”逻辑，不需要在整个代码中复制它：

class DecimalHelper:

    def __init__(self, row, column):
        self.row = row
        self.column = column

        self.rowIndex = row - 1
        self.colIndex = column - 1


row = 3
column = 4

dc = DecimalHelper(row, column)

print dc.rowIndex
print dc.colIndex

还有一种更优雅的方式，使用类属性（this帖子的信用）：

class ClassPropertyDescriptor(object):

    def __init__(self, fget, fset=None):
        self.fget = fget
        self.fset = fset

    def __get__(self, obj, klass=None):
        if klass is None:
            klass = type(obj)
        return self.fget.__get__(obj, klass)()

    def __set__(self, obj, value):
        if not self.fset:
            raise AttributeError("can't set attribute")
        type_ = type(obj)
        return self.fset.__get__(obj, type_)(value)

    def setter(self, func):
        if not isinstance(func, (classmethod, staticmethod)):
            func = classmethod(func)
        self.fset = func
        return self    

def classproperty(func):
    if not isinstance(func, (classmethod, staticmethod)):
        func = classmethod(func)

    return ClassPropertyDescriptor(func)

class DecimalHelper:

    def __init__(self, row, column):
        self.row = row
        self.column = column

    @classproperty
    def rowIndex(cls):
        return row - 1

    @classproperty
    def colIndex(cls):
        return column - 1

row = 3
column = 4

dc = DecimalHelper(row, column)

print dc.rowIndex
print dc.colIndex

我可以将这两个赋值语句放在辅助函数中吗？

2 个答案: