CODEWITHSUNDEEP
pythonpalindrome
pk.
pk.

Reputation: 99

I want to find out all the palindrome prime numbers between 2 numbers. My code can find the palindrome numbers but also prints the non primes

Non-prime numbers are being printed because it checks only from '2-10' for prime numbers. How can I change the code to check for all numbers upto x?

N = eval(input("Enter the starting point N: \n"))
M = eval(input("Enter the ending point M: \n"))

n = str(N)

i = 0


for j in range(N, M):
    if (n[i] == n[len(n)-1]):
        x = N
        N = N + 1
        if not((x % 2 == 0) or (x % 3 == 0) or (x % 4 == 0) or (x % 5 == 0) or (x % 6 == 0) or (x % 7 == 0) or (x % 8 == 0) or (x % 9 == 0) or (x % 10 == 0)):
            print(x)
        n = str(N)

    else:
        N = N + 1
        n = str(N)

Upvotes: 0

Views: 1471

Answers (2)

reticentroot
reticentroot

Reputation: 3682

Heres a palindrome snippet

low_range = input()
high_range = input()
string_convertor = str

for num in range(int(low_range), int(high_range)):
    num_to_string = string_convertor(num)
    reverse = num_to_string[::-1]
    if num_to_string == reverse:
        print("Palindrome")
        print(num_to_string)

Upvotes: 0

pzp
pzp

Reputation: 6607

Here's an implementation of the Sieve of Eratosthenes that I wrote. It pretty efficiently finds all the prime numbers less than the number you pass it. I would explain it to you, but Wikipedia (linked above) does a much better job than I could. Use it to generate the prime numbers and then iterate through the list it returns to check if those numbers are palindromes.

def primeslt(n):
    """Finds all primes less than n"""

    if n < 3:
        return []

    A = [True] * n
    A[0], A[1] = False, False

    for i in range(2, int(n**0.5)+1):
        if A[i]:
            j = i**2
            while j < n:
                A[j] = False
                j += i

    return [num for num in range(n) if A[num]]

Upvotes: 1

Related Questions