[FIXED] can't make a programm that counts nonterminal nodes in a tree

Issue

This is a syntactic tree and it looks like this in the form of code

My program is supposed to count the number of non-terminal nodes on that tree. The idea is that every tree is a 2 tuple. On the first position stands the mother node as a string and on the second position stands either a string if there is a terminal node or a list with daughter trees of the mother node. They are recursive. The program should count the number of nonterminal nodes. so the result should just be a number of nonterminal nodes, e.g. 9.

So far as I have understood, I should do this using recursion. But there are some things that I fail to do correctly to make my programm work. My code is:

tuple_list = []
second_tuple_elements = [a_tuple[1] for a_tuple in tuple_list]
print(second_tuple_elements)
def nonterminal(count):

    if second_tuple_elements == type(""):

        return 1

    if second_tuple_elements == type([]):
        for element in list:
            if element == type (""):
                return 1
            nonterminal = second_tuple_elements + element

Solution

Here's a solution:

def count_nodes(tree):
    count = 0

    if isinstance(tree, str):
        return 0
    node, rest = tree 
    count +=1 
    for subtree in rest: 
        count += count_nodes(subtree)

    return count

Answered By - Roy2012