def print_square_list(list_to_square):
    '''prints out each element of the list squared'''
    for current_num in list_to_square:
        print(current_num ** 2)
        

def print_negative_items(some_list):
    '''print only the negative elements of some_list'''
    for num in some_list:
        if num < 0:
            print(num)


def sum_positive(some_list):
    '''returns the sum of the positive elements of some_list'''
    sum_so_far = 0
    for num in some_list:
        if num > 0:
            sum_so_far += num
    return sum_so_far


def get_negative_items(some_list):
    '''return a list of all the negative elements of some_list'''
    negative_list = [] # negative items so far
    for num in some_list:
        if num < 0:
            negative_list.append(num)
    return negative_list


def extract_uppercase(string):
    '''returns a new string of just the uppercase letters of string'''
    upper = ''
    for char in string:
        if char.isupper():
            upper += char
    return upper
    

def list_max(some_list):
    '''returns the maximum value of some_list'''
    best_so_far = some_list[0]
    for num in some_list:
        if num > best_so_far:
            best_so_far = num
            print("best answer is ", best_so_far)
    return best_so_far


def list_length(some_list):
    '''return the length of some_list'''
    num_elements = 0
    for current_num in some_list:
        num_elements += 1
    return num_elements