55
66
77def prime_check (number : int ) -> bool :
8- """
9- Check to See if a Number is Prime.
8+ """Checks to see if a number is a prime.
109
11- A number is prime if it has exactly two dividers : 1 and itself.
10+ A number is prime if it has exactly two factors : 1 and itself.
1211 """
13- if number < 2 :
14- # Negatives, 0 and 1 are not primes
15- return False
16- if number < 4 :
12+
13+ if 1 < number < 4 :
1714 # 2 and 3 are primes
1815 return True
19- if number % 2 == 0 :
20- # Even values are not primes
16+ elif number < 2 or not number % 2 :
17+ # Negatives, 0, 1 and all even numbers are not primes
2118 return False
2219
23- # Except 2, all primes are odd. If any odd value divide
24- # the number, then that number is not prime.
25- odd_numbers = range (3 , int (math .sqrt (number )) + 1 , 2 )
26- return not any (number % i == 0 for i in odd_numbers )
20+ odd_numbers = range (3 , int (math .sqrt (number ) + 1 ), 2 )
21+ return not any (not number % i for i in odd_numbers )
2722
2823
2924class Test (unittest .TestCase ):
@@ -40,12 +35,17 @@ def test_primes(self):
4035 self .assertTrue (prime_check (29 ))
4136
4237 def test_not_primes (self ):
43- self .assertFalse (prime_check (- 19 ), "Negative numbers are not prime." )
4438 self .assertFalse (
45- prime_check (0 ), "Zero doesn't have any divider, primes must have two."
39+ prime_check (- 19 ),
40+ "Negative numbers are excluded by definition of prime numbers." ,
41+ )
42+ self .assertFalse (
43+ prime_check (0 ),
44+ "Zero doesn't have any positive factors, primes must have exactly two." ,
4645 )
4746 self .assertFalse (
48- prime_check (1 ), "One just have 1 divider, primes must have two."
47+ prime_check (1 ),
48+ "One only has 1 positive factor, primes must have exactly two." ,
4949 )
5050 self .assertFalse (prime_check (2 * 2 ))
5151 self .assertFalse (prime_check (2 * 3 ))
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