python - Displaying 0 instead of None in Web2py app -

as mentioned in title, want display 0 instead of none session.counter or session.wrong_counter in web2py app. have tried 10 different ways not getting right reason.

this controller page score:

def score():     image = db.pic(request.args(0,cast=int)) or redirect(url('index'))     correct = image.id == session.pic_id     next_game = random.randint(1, 35)     wrong_counter = []     right_counter = []     if correct:         session.counter = (session.counter or 0)+1         right_counter=session.counter     if not correct:         session.wrong_counter = (session.wrong_counter or 0)+1         wrong_counter=session.wrong_counter     return locals() 

in view have {{=session.counter}} , {{=session.wrong_counter}}. when page score first visited during session 1 of them display 1 , other display none depending on correct or not correct conditions expected, however, want display 0 instead of none.

i appreciate advise.

simply initialize wrong_counter value 0 when correct true, , wrong_counter not set:

if correct:     session.counter = (session.counter or 0)+1     right_counter=session.counter     if not session.wrong_counter:        # first time have correct answer        wrong_counter = 0     else:        wrong_counter = (session.wrong_counter or 0)+1     session.wrong_counter = wrong_counter if not correct:     session.wrong_counter = (session.wrong_counter or 0)+1     wrong_counter=session.wrong_counter 

that way, instead of having none default value, have 0.

however, have set right_counter , wrong_counter empty lists above loop. if set these value of session variables, make logic easier:

right_counter = session.counter or 0 wrong_counter = session.wrong_counter or 0  if correct:    right_counter = int(right_counter) + 1 if not correct:    wrong_counter = int(wrong_counter) + 1  session.counter = right_counter session.wrong_counter = wrong_counter