python function to check prime number code example

Example 1: how to check if a number is prime in python

def prime(num):
        for x in range(2,num):
            if num % x == 0:
                return False
        return True

Example 2: 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 3: prime number in python

def prime(num):
    if num>1:
        s=int(num/2)
        for i in range(2,s+1):
            if num%i==0:
                return("not prime")
                break
        return("prime")
print(prime(239))

Example 4: how to check if a number is prime in python

import math
def prime(x):
    if x == 2 or x == 3 or x==5:
        return True
    if x == 1 or x == 4:
        return False
    num = 2
    a= math.sqrt(x)+4 
    while a > num:
        if x % num == 0:
            return False
        else:
            num = num + 1
    return True

Example 5: prime number program python

# Python program to display all the prime numbers within an interval

lower = 900
upper = 1000

print("Prime numbers between", lower, "and", upper, "are:")

for num in range(lower, upper + 1):
   # all prime numbers are greater than 1
   if num > 1:
       for i in range(2, num):
           if (num % i) == 0:
               break
       else:
           print(num)Copied

Example 6: check if a number is prime python

n=input('Enter the number you want to check: ')
try:
    n=int(n)
except:
    print('Wrong input.')
    quit()
if n==1 or n==0:
    print('This is neither prime nor composite')
else:
    c=0
    for i in range(2,n):
        if n%i==0:
            c=c+1
    if c==0:
        print("This is a prime number")
    else:
        print('This  is a composite number.')