prime number python code example

Example 1: prime factorization python

import math


def primeFactors(n):
    # no of even divisibility
    while n % 2 == 0:
        print(2)
        n = n / 2
    # n reduces to become odd
    for i in range(3, int(math.sqrt(n)) + 1, 2):
        # while i divides n
        while n % i == 0:
            print(i)
            n = n / i
    # if n is a prime
    if n > 2:
        print(n)


primeFactors(256)

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: prime checker in python

#make the function
#to do this all hte vairibles go in side the function

def CheckIfPrime ():
    a1 = input("which number do you want to check")
    a = int(a1)#you need the checking number as an int not an str
    b = 2 #the number to check againts
    c = ("yes")
    while b < a:#run the loop
        if a%b == 0:#check if the division has a remainder
            c = ("no")#set the answer
        b = b+1
    print(c)#print the output
CheckIfPrime ()#call the function

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.')