prime number or not in python code example
Example 1: determine if number is prime python
# Time Efficient Primality Check in Python
def primeCheck(n):
# 0, 1, even numbers greater than 2 are NOT PRIME
if n==1 or n==0 or (n % 2 == 0 and n > 2):
return "Not prime"
else:
# Not prime if divisable by another number less
# or equal to the square root of itself.
# n**(1/2) returns square root of n
for i in range(3, int(n**(1/2))+1, 2):
if n%i == 0:
return "Not prime"
return "Prime"
Example 2: Program to check if a number is prime or not in Python
# Program to check if a number is prime or not
num = 29
# To take input from the user
#num = int(input("Enter a number: "))
# define a flag variable
flag = False
# prime numbers are greater than 1
if num > 1:
# check for factors
for i in range(2, num):
if (num % i) == 0:
# if factor is found, set flag to True
flag = True
# break out of loop
break
# check if flag is True
if flag:
print(num, "is not a prime number")
else:
print(num, "is a prime number")