23  Working with Decision Structures

23.1 Task : Creating a selective List

23.2 Task : Managing a selective List

• File decisions.py

def mydecision(list1,list2):    
    return [list1[index] for index in evens(len(list1))], [list2[index] for index in evens(len(list2))]

def mydecision2(list1,list2):
    return [list1[index] for index in odds(len(list1))], [list2[index-1] for index in primes(len(list2)+1)]


def odds(end):
    odd = []
    for x in range(0,end):
        if x % 2 != 0:
            odd.append(x)
    return odd

def evens(end):
    even = []
    for x in range(0,end):
        if x % 2 == 0:
            even.append(x)
    return even


def isprime(num):
    if num < 2:
        return False
    
    for i in range(2, num):
        if (num % i) == 0:
            #print(i)
            break
    else:
        return True
    return False


def primes(end):
    prime = []
    for x in range(0,end):
        if x % 2 != 0:
            if isprime(x):
                prime.append(x)
    return prime


def indexes(end):
    odd = odds(end)
    even = evens(end)
    prime = primes(end)

    return odd, even, prime