Check a number is Prime or not in Python

Question

def main():

n = input("Please enter a number:")
is_prime(n)

def is_prime(a):
    x = True 
    for i in (2, a):
            while x:
               if a%i == 0:
                   x = False
               else:
                   x = True


    if x:
        print "prime"
    else:
        print "not prime"

main()

If the entered number is not a prime number, it displays "not prime", as it is supposed to, but if the number is a prime number, it doesn't display anything. Could you please help me with it?

Answer 1

There is an efficient way to write the same program. 

The loop you wrote can be concisely rewritten in Python:

def is_prime(a):
    return all(a % i for i in xrange(2, a))

That is, a is prime if all numbers between 2 and a (not inclusive) give non-zero remainder when divided into a.

Answer 2

number = int(input("Enter the Number"))
if(number==1):
    print(number,"is not prime Number")
elif(number==0):
    print("Oh! Enter the natural number to check the prime or not")
else:
    check =number//2
    for i in range(2 ,check+1):
        if check%i==0:
            print("oh! sorry",number,"is not prime Number")
            break
    else:
        print("congratulation!",number,"is the Prime Number")

Comments

Thanks a lot Anand, this solved my problem. Upvoting your answer right away... :)