just indent your code correctly:
def determine_period(universe_array):
period=0
tmp=universe_array
while True:
tmp=apply_rules(tmp)#aplly_rules is a another function
period+=1
if numpy.array_equal(tmp,universe_array) is True:
return period
if period>12: #i wrote this line to stop it..but seems its doesnt work....help..
return 0
else:
return period
You need to understand that the break statement in your example will exit the infinite loop you've created with while True. So when the break condition is True, the program will quit the infinite loop and continue to the next indented block. Since there is no following block in your code, the function ends and don't return anything. So I've fixed your code by replacing the break statement by a return statement.
Following your idea to use an infinite loop, this is the best way to write it:
def determine_period(universe_array):
period=0
tmp=universe_array
while True:
tmp=apply_rules(tmp)#aplly_rules is a another function
period+=1
if numpy.array_equal(tmp,universe_array) is True:
break
if period>12: #i wrote this line to stop it..but seems its doesnt work....help..
period = 0
break
return period