Why does my Python while loop run forever and never stop?

An infinite loop almost always means the loop condition never becomes False because you forgot to update the variable inside the loop. For example, 'i = 1; while i <= 5: print(i)' runs forever because i stays 1. You must change the control variable each iteration: add 'i = i + 1' (or 'i += 1') as the last line inside the loop. Now i grows to 6, the condition i <= 5 becomes False, and the loop stops. Always check three things: the variable is initialised before the loop, the condition will eventually be False, and the variable is updated inside the loop. If any one is missing, the loop runs forever.