Question

How to check if a number is prime in Python

Answer 1

import math
import random

def is_prime(num):
    if num == 0:
        return 0
    if num == 1:
        return 0
    for p in range(2, int(round(math.sqrt(num))) + 1):
        if int(round(num % p)) == 0:
            return 0
    return 1


for i in range(1, 20 + 1):
    n = random.randint(1, 100)
    if is_prime(n):
        print(n , "- Prime")
    else:
        print(n , " - NOT Prime")



'''
run:

94  - NOT Prime
6  - NOT Prime
73 - Prime
51  - NOT Prime
56  - NOT Prime
13 - Prime
18  - NOT Prime
20  - NOT Prime
99  - NOT Prime
100  - NOT Prime
34  - NOT Prime
51  - NOT Prime
50  - NOT Prime
45  - NOT Prime
87  - NOT Prime
13 - Prime
17 - Prime
93  - NOT Prime
53 - Prime
4  - NOT Prime

'''

 

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Answer 2

def isPrime(n):
    if n < 2: return False
     
    for i in range(2, n):
        if n % i == 0:
            return False
    return True
     
n = 97
  
if (isPrime(n)) :
    print("Prime number")
else :
    print("Not prime number")
 
  
  
  
'''
run:
  
Prime number
  
'''

 

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Answer 3

from sympy import isprime
 
print(isprime(97))
 
print(isprime(31))
 
print(isprime(16))
  
  
  
'''
run:
  
True
True
False
 
'''

 

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Answer 4

def isPrime(n):
    if n < 2: return False
      
    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            return False
    return True
      
n = 97
   
if (isPrime(n)) :
    print("Prime number")
else :
    print("Not prime number")
  
   
   
   
   
'''
run:
   
Prime number
   
'''

 

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Answer 5

import math

def is_prime(n):
    if n < 2:
        return False
    if n == 2:
        return True
    if n % 2 == 0:
        return False
    for i in range(3, int(math.sqrt(n)) + 1, 2):
        if n % i == 0:
            return False
    return True

print(is_prime(47))
print(is_prime(100))



'''
run

True
False

'''

 

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