我在使用 Python 时遇到了一些问题,所以这是我的类(class):
class Rectangle:
def __init__(self, x1=0, y1=0, x2=0, y2=0):
if(x1 > x2):
raise ValueError("x1 cannot be bigger than x2!")
if(y1 > y2):
raise ValueError("y1 cannot be bigger than y2!")
self.pt1 = Point(x1, y1)
self.pt2 = Point(x2, y2)
def __str__(self):
return str("[(" + str(self.pt1.x) + ", " + str(self.pt1.y) + "), (" + str(self.pt2.x) + ", " + str(self.pt2.y) + ")]")
def __repr__(self):
return str("Rectangle(" + str(self.pt1.x) + ", " + str(self.pt1.y) + ", " + str(self.pt2.x) + ", "+ str(self.pt2.y) + ")")
def __eq__(self, other):
return (self.pt1== other.pt1 and self.pt2 == other.pt2)
def __ne__(self, other):
return not self == other
def center(self):
return Point((self.pt2.x - self.pt1.x) / 2, (self.pt2.y - self.pt1.y) / 2)
当我尝试在另一个类中使用方法“center”时:
class TestRectangle(unittest.TestCase):
def setUp(self):
self.first = Rectangle(1, 2, 3, 4)
self.second = Rectangle(2, 2, 4, 5)
def test_init(self):
with self.assertRaises(ValueError):
Rectangle(5, 1, 2, 3)
self.assertEqual(self.first.pt1, Point(1, 2))
self.assertEqual(self.first.pt2, Point(3, 4))
self.assertEqual(self.second.pt1.x, 2)
def test_str(self):
self.assertEqual(str(self.first), "[(1, 2), (3, 4)]")
def test_repr(self):
self.assertEqual(repr(self.first), "Rectangle(1, 2, 3, 4)")
def test_eq(self):
self.assertTrue(self.first == Rectangle(1,2,3,4))
self.assertFalse(self.first == self.second)
def test_ne(self):
self.assertFalse(self.first != Rectangle(1,2,3,4))
self.assertTrue(self.first != self.second)
def test_center(self):
self.assertEqual(self.first.center(), Point(2, 2.5))
我收到这条消息:
Rectangle instance has no attribute "center".
我现在不知道怎么办,为什么它看不到我的方法?
最佳答案
阅读您的代码,由于缩进错误,您似乎在 Rectangle
类之外定义了 center
。
因此,Rectangle
实例没有任何center
方法。
我尝试了正确的缩进,它确实有效。
关于 python "instance has no attribute ...",我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40878575/