python code to check prime number consider (55,25 ) is prime number

Question

snap shot for code the python program to check prime number in list of number consider 55 and 25 as prime number which is actually not prime because 55/5=11 and reminder is zero so what problem in code

def check_prime(n):
    for i in range(2,n,1):
        if(n%i)==0:
            return  1
        else :
            return 0

numbers=[51,52,53,54,55,13,407,508,11,17,60,12,19,25,30,]
for j in numbers:
    if check_prime(j)==1:
        print("the {} is not prime".format(j))
    else:
        print("th {} is prime".format(j))

May I suggest flipping the return values? It has nothing to do with your issue, but if you see the function name check_prime as a question of "is this a prime number?", then you'd prefer a return value of 1 to be yes and 0 to be no. — Kroshtan, Apr 23 '20 at 18:28

score 0 · Answer 1 · answered Apr 23 '20 at 18:27

because, you put return in your function, and for this reason your function only do the first evaluation in other your function only return if a number is odd or ever, because only evaluate when i = 2, your function has to be.

def check_prime(n):
   for i in range(2,n):
      if(n%i)==0:return False
   return True

score 0 · Accepted Answer · answered Apr 23 '20 at 18:28

0

You have a logical error in check_prime function, try this :

def check_prime(n):
    for i in range(2, n, 1):
        if (n % i) == 0:
            return True
    return False


numbers = [51, 52, 53, 54, 55, 13, 407, 508, 11, 17, 60, 12, 19, 25, 30, ]
for j in numbers:
    if check_prime(j):
        print("the {} is not prime".format(j))
    else:
        print("th {} is prime".format(j))

answered Apr 23 '20 at 18:28

Taohidul Islam

5,246
3
26
39

ok thank very much but why code return this error with only number that accept dividable by 5 – kamal kareem Apr 23 '20 at 18:58

score 0 · Answer 3 · answered Apr 23 '20 at 18:30

0

Your function returns after a single iteration, cancelling the effect of your for loop. You want to return when finding its not a prime number, but you need to continue looping through all numbers before you can say a prime number is prime. Also, flipped the return values to make more intuitive sense.

def check_prime(n):
    for i in range(2,n,1):
        if(n%i)==0:
            return  0
    return 1

answered Apr 23 '20 at 18:30

Kroshtan

637
5
17

but why return number 11 as prime number 19 as prime a – kamal kareem Apr 23 '20 at 18:44
Because they all fail on x%2==0 and then stop looping, so they are all labeled prime. For 11 and 19 this is correct, but not for 25 and 55. – Kroshtan Apr 25 '20 at 06:14

score 0 · Answer 4 · answered Apr 23 '20 at 18:44

0

You need to make the return in your loop conditional. It will exit after a single loop in this case, which is why you are seeing it return false positives.

answered Apr 23 '20 at 18:44

Jesse Ronco

1
1

python code to check prime number consider (55,25 ) is prime number

4 Answers4