如果涉及方法内部变量的scope，python与java是否不同？

Question

I am writing the following code:

class NewList():

    def __init__(self,initial_state):
        self.data = initial_state

    def append(self,new_item):
        self.data = self.data + [new_item]
        self.big = self.data

    def deppend(self,new_item):
        self.data = self.data + [new_item]
        self.big = self.big + [new_item]


    my_list = NewList([1,2,3,4,5])
    print(my_list.data)
    my_list.append(6)
    print(my_list.data)
    print(my_list.big)
    my_list.deppend(7)
    print(my_list.data)
    print(my_list.big)

I don't think variables such as data,big etc that are declared inside a method can be used in another method in Java. But, here in python we are easily able to use them. Is it that the variables declared inside a method in python have a global scope rather than java that has a local scope??

Answer 1

The variable you have defined are declared using self keyword. Think of it as this in java.

So when you do self.big = self.data The big becomes the attribute of the object. Hence it is accessible with the object.

obj.attribute and self.attribute are essentially the same. And in python, you can create new attributes at fly.