combination_list = []

def combination(alist):
    """
    Recursion method imlementation
    """
    if len(alist) == 2:
        combination_list.append(tuple(alist))
    else:
        for i in alist[1:]:
            combination_list.append((alist[0],i))
        return combination(alist[1:])

def combination_for(alist):
    """
    For loop method implementaion
    """
    for i in alist[:-1]:
        for j in alist[i+1:]:
            combination_list.append((i,j))

if __name__ == "__main__":
    alist = [i for i in range(10)]
    # combination(alist)
    combination_for(alist)
    print(combination_list)