获取TypeError:\uuuu str\uuuuu在Python中返回了非字符串（类型元组）错误

Question

我不熟悉Python中的类，我正在尝试打印这个方形对象。但是，我一直收到一个错误，它是TypeError:str返回非字符串（type tuple）。告诉我检查第29行和第32行

class Square:
    def __init__(self, lenSide, color):
        self.lenSide = lenSide
        self.color = color
    def __repr__(self):
        return self.lenSide, self.color
    def getSide(self, lenSide):
        return lenSide
    def getArea(self, lenSide):  # return area
        print(lenSide + lenSide)
    def getPerm(self, lenSide):  # return perimeter
        print(self.lenSide*4)
    def setColor(self, color):  # return color
        self.color = color
    def describe(self, color, lenSide):
        print("I am a " + self.color + " square with side" + self.lenSide)
def mySquare():
    newSquare = Square(5, "red")
    print(newSquare)
mySquare()
 

Answer 1

如注释中所述，repr方法的目标是“以字符串格式返回对象表示形式”。目前，您的实现正在返回元组

您只需将repr修改为以下内容：

def __repr__(self):
    return 'Length:' + str(self.lenSide) + ' ' + 'Color:' + self.color

Answer 2

^{}

Called by the repr() built-in function to compute the “official” string representation of an object. The return value must be a string object.

^{}

Called by str(object) and the built-in functions format() and print() to compute the “informal” or nicely printable string representation of an object. The return value must be a string object.

因此，必须返回字符串对象，而不是非字符串（在本例中为元组）

def __repr__(self):
    return str(self.lenSide) + ' ' + str(self.color)

Answer 3

从文档中：

Return a string containing a printable representation of an object.

__repr__特殊方法用于返回字符串。返回的不是字符串，而是元组(self.lenSide, self.color)。要将元组转换为字符串，可以使用str()。因此__repr__方法应该返回str((self.lenSide, self.color))（注意额外的parentases以形成元组）

另见： What is the difference between str and repr?