将函数返回的值分配给Python中的变量

Question

I began coding in Python recently and encountered a problem assigning the value returned by a function to a variable.

class Combolock:
    def _init_(self,num1,num2,num3):
        self.x = [num1,num2,num3]
    def next(self, state):
        print "Enter combination"
        combo = raw_input(">")
        if combo == self.x[state]:
            print "Correct"
            return 1
        else:
            print "Wrong"
            return 0
    def lock(self):
        currentState = 0
        while currentState < 2:
            temp = next(currentState)
            if temp == 1:
                currentState = currentState + 1
            else:
                currentState = 99
                print "ALARM"

When I call the lock function, I get an error at the line

temp = next(currentState)

saying that an int object is not an iterator.

Answer 1

You should use self.next(currentState) , as you want the next method in the class scope.

The function next is global and next(obj) works only if obj is an iterator .
You might want to have a look at the yield statement in the python documentation.

Answer 2

As Andrea (+1) pointed it out you need to tell python you want to call next() method on self object, so you need to call it self.next(currentState) .

Also, note, that you have defined incorrect initializer (aka. constructor). You have to use double underscores:

__init__(...

instead of:

_init_(...

otherwise it is just a method - not called while object creataion.

Answer 3

请改用self.next（currentState），否则它指的是迭代器的next（）方法，而不是你的类

Answer 4

The error means just what it says. When you use next(iterable) , next tries to call the iterable 's next method . However, when you do dir(0) :

['__abs__',
 # ... snip ...
 '__xor__',
 'bit_length',
 'conjugate',
 'denominator',
 'imag',
 'numerator',
 'real']

As you can see, there is no next method on an integer.

If you are trying to call your own next method, then you need to use self.next not next . next is a builtin function that calls the next method of an iterator to let you do things like this:

 for something in my_iterator:
     print something

Try:

temp = self.next(currentState)