CODEWITHSUNDEEP
python
anjan kumar
anjan kumar

Reputation: 11

Why is this code printing None?

Tried to execute the below program along with values its printing None. Can anyone help me why its printing None?

class Myself(object):
    def __init__(self):
        self.record={}
    def __iter__(self):
        self._roles = list(self.record.keys())
        #print ("in iter self._roles",type(self._roles))
        return self
    def __next__(self):
        if self._roles:
            return self._roles.pop()
        else:
            StopIteration

    def __setitem__(self,key,value):
        self.record[key]=value
    def __getitem__(self,key):
        return self.record.get(key,"No record found")

    def list_all(self):
        for detail in self.record:
            print (self.record[detail])

def main():
    mydetails = Myself()

    mydetails['name']='Python'
    mydetails['age']='26'
    mydetails['job']='software'
    mydetails.list_all()

    for x in mydetails:
        print (x,":",mydetails[x])

main()

Upvotes: 1

Views: 61

Answers (2)

Martijn Pieters
Martijn Pieters

Reputation: 1121924

You need to raise the StopIteration execption:

def __next__(self):
    if self._roles:
        return self._roles.pop()
    else:
        raise StopIteration

Because you don't raise it, you are merely referencing the name, which does nothing. Then the __next__ method just ends, resulting in a default implicit return None.

Upvotes: 1

Daniel
Daniel

Reputation: 42758

You should raise StopIteration:

def __next__(self):
    if self._roles:
        return self._roles.pop()
    else:
        raise StopIteration

Upvotes: 1

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