I have function a call function b (returns True or False to a), afterwards function a can return the result to be printed.
class C:
...
def a(self, data):
p = self.head
return self.b( p,data)
def b(self, p, data):
current = p
if current.data == data:
return True
else:
return False
if __name__=="__main__":
x = C()
print(x.a(1))
Sometimes it returns None eventhough it is intended to be True. I'm not sure what happened?
This question is related to
python
It's impossible to say without seeing your actual code. Likely the reason is a code path through your function that doesn't execute a return statement. When the code goes down that path, the function ends with no value returned, and so returns None.
Updated: It sounds like your code looks like this:
def b(self, p, data):
current = p
if current.data == data:
return True
elif current.data == 1:
return False
else:
self.b(current.next, data)
That else clause is your None path. You need to return the value that the recursive call returns:
else:
return self.b(current.next, data)
BTW: using recursion for iterative programs like this is not a good idea in Python. Use iteration instead. Also, you have no clear termination condition.
Source: Stackoverflow.com