带有关键字“and”的条件 if 语句给了我意想不到的结果

Question

I'm a new programmer so this is probably not efficient but I'm finding this issue curious to me. Look at the function countDigitsCheck below and notice the if statement is checking if the variable, count_check_one and variable, count_check_two == 1. If they are both == 1 then it multiplies a * b. You can see in the output that count_check_one is == 3 (not 1) and count_check_two == 1. Since one of the integers is == 3 the two integers should NOT multiply. However, you'll notice in the output the integers are multiplying to 900. I understand that if I had used "or" instead of "and" in the if statement I would expect this behavior, but not when I use "and". Please help me to understand why they are still multiplying. Thanks.

def karatsubaAlgorithm(x,y):
  return(countDigitsCheck(x,y))

def countDigitsCheck(one, two):
  count_check_one = countDigits(one)
  count_check_two = countDigits(two)
  a = one
  b = two
  print(count_check_one)
  print(count_check_two)
  if count_check_one and count_check_two == 1:
    answer = a * b
    return(answer)

def countDigits(number):
  Number = number
  Count = 0
  while(Number > 0):
    Number = Number // 10
    Count = Count + 1
  return(Count)

check_function = karatsubaAlgorithm(100,9)
print(check_function)


OUTPUT:
3
1
900

Answer 1

Your if statement is essentially if (count_check_one) and (count_check_two == 1): This means that as long as the value of count_check_one is not 0, the first condition will be true since in Python every integer evaluates to true except 0. If you want to check if both count_check_one and count_check_two are equal to 1, you will have to do if count_check_one == 1 and count_check_two == 1: . This will check if both variables are 1.