Understanding - Advanced, exercise 10

Text

The variable my_gn contains the string of a given name in lowercase (e.g. "john"), the variable my_fn contains the string of a family name in lowercase (e.g. "doe"), and the variable my_mn contains the string of ten 0-9 digits. Study the execution of the following functions when they are called as follows: char_n(my_gn, my_fn, my_mn).

def r_char(idx, c_str, c_set):
    cur_c = c_str[idx % len(c_str)]
    if cur_c in c_set:
        c_set.remove(cur_c)


def char_n(gn, fn, mn):
    result = 0

    gn_set = set(gn.replace(" ", ""))
    fn_set = set(fn.replace(" ", ""))

    rn = 0
    for n in mn:
        rn += int(n)

    r_char(rn, gn, gn_set)
    r_char(rn, fn, fn_set)

    n_set = gn_set.union(fn_set)
    for idx in range(len(n_set)):
        if str(idx) in mn:
            result = result + idx
        else:
            result = result - idx

    return result

Hints

The function char_n starts from the characters included in the two names (given and family) in input, that are then modified according to digits in input. Then, all the characters in the given and family names, appropriately modified as mentioned, are processed again to create the result value.

Additional material

The runnable Python file is available online. You can run it executing the command python exercise_10.py in a shell, and then following the instructions on screen to specify the intended input.