我运行这样的代码：
def funtest(L=[]):
L.append(L)
return L
print(funtest([2]))
print(funtest([3]))
print(funtest([4]))
实际输出在下面。
[2, [...]]
[3, [...]]
[4, [...]]
I know a very heated discussion about the Mutable Default Arguments in before: Least Astonishment” and the Mutable Default Argument
根据Mutable Default Arguments规则，我认为输出应为：
[2, [...]]
[2,3, [...]]
[2,3,4, [...]]
有人对此有想法吗？谢谢
当您不向函数传递任何参数时，默认参数就会出现
here you are passing arguments to the function namely
[2],[3]and[4]and hence default value is not being usedin your question you mention that for first print output should be
[2, [...]]if you are able to understand that , then next ones are exactly same as default argument never comes in the picture.. just focus on how[2, [...]]came