Python Practice Programs

Task 1:

List the prime and composite number from 2 to 31.

def findPrime(no):
    i = 2
    while i < no:
        if no % i == 0:
            return 'Composite number'
        i+=1
    else:
        return 'Prime number'    

n = 2
while n <= 31:
    result = findPrime(n)
    print(f'{n} is {result}')
    n+=1

Output:

2 is Prime number
3 is Prime number
4 is Composite number
5 is Prime number
6 is Composite number
7 is Prime number
8 is Composite number
9 is Composite number
10 is Composite number
11 is Prime number
12 is Composite number
13 is Prime number
14 is Composite number
15 is Composite number
16 is Composite number
17 is Prime number
18 is Composite number
19 is Prime number
20 is Composite number
21 is Composite number
22 is Composite number
23 is Prime number
24 is Composite number
25 is Composite number
26 is Composite number
27 is Composite number
28 is Composite number
29 is Prime number
30 is Composite number
31 is Prime number

Task 2:

Find 42 as sum of 2 consecutive prime numbers.

def findPrime(no):
    i = 2
    while i < no:
        if no % i == 0:
            return False
        i+=1
    else:
        return no    

no = 3
n1 = 2
while True:
    n2 = findPrime(no)

    if n2 != False:
        if n1 + n2 == 42:
            print(n1, n2)
            break
        else:
            n1 = n2
    no+=1

Output:

19 23

Task 3
Find Twin Primes? A pair of prime numbers whose difference is 2.

def findPrime(no):
    i = 2
    while i < no:
        if no % i == 0:
            return False
        i+=1
    else:
        return no    

no = 3
n1 = 2
while no <= 100:
    n2 = findPrime(no)

    if n2 != False:
        if n2 - n1 == 2:
            print(n1, n2)
        # else:
        n1 = n2
    no+=1

Output:

3 5
5 7
11 13
17 19
29 31
41 43
59 61
71 73

Task 4:
Find the program, if the number is divisible by 2.

n = 11

if n % 2 == 0:
    print("Divisible by 2")
else:
    print("Not Divisible by 2") 

Output:

11 is not Divisible by 2

Task 5:
Find the program, if the number is divisible by 3.

n = 96

if n % 3 == 0:
    print("Divisible by 3")
else:
    print("Not Divisible by 3") 

no = 96

onesPlace = no % 10
tensPlace = no // 10

sum = onesPlace  + tensPlace

if sum % 3 == 0:
    print("Divisible by 3")
else:
    print("Not Divisible by 3")    

Output:

Divisible by 3