python prime checker

1# Time Efficient Primality Check in Python
2
3def primeCheck(n):
4    # 0, 1, even numbers greater than 2 are NOT PRIME
5    if n==1 or n==0 or (n % 2 == 0 and n > 2):
6        return "Not prime"
7    else:
8        # Not prime if divisable by another number less
9        # or equal to the square root of itself.
10        # n**(1/2) returns square root of n
11        for i in range(3, int(n**(1/2))+1, 2):
12            if n%i == 0:
13                return "Not prime"
14        return "Prime"

1def isPrime(n):
2  if n<2:		#1, 0 and all negative numbers are not prime
3    return False
4  elif n==2:	#2 is prime but cannot be calculated with the formula below becuase of the range function
5    return True
6  else:
7    for i in range(2, n):
8      if (n % i) == 0:	#if you can precisely divide a number by another number, it is not prime
9        return False
10    return True			#if the progam dont return False and arrives here, it means it has checked all the numebrs smaller than n and nono of them divides n. So n is prime

1#make the function
2#to do this all hte vairibles go in side the function
3
4def CheckIfPrime ():
5    a1 = input("which number do you want to check")
6    a = int(a1)#you need the checking number as an int not an str
7    b = 2 #the number to check againts
8    c = ("yes")
9    while b < a:#run the loop
10        if a%b == 0:#check if the division has a remainder
11            c = ("no")#set the answer
12        b = b+1
13    print(c)#print the output
14CheckIfPrime ()#call the function  
15

1# Program to check if a number is prime or not
2
3num = 29
4
5# To take input from the user
6#num = int(input("Enter a number: "))
7
8# define a flag variable
9flag = False
10
11# prime numbers are greater than 1
12if num > 1:
13    # check for factors
14    for i in range(2, num):
15        if (num % i) == 0:
16            # if factor is found, set flag to True
17            flag = True
18            # break out of loop
19            break
20
21# check if flag is True
22if flag:
23    print(num, "is not a prime number")
24else:
25    print(num, "is a prime number")