Computes the average dependency parse tree height for a sequence of sentences

average_parse_tree_height.py

import spacy
import numpy as np

nlp = spacy.load('en', disable=['ner'])


def tree_height(root):
    """
    Find the maximum depth (height) of the dependency parse of a spacy sentence by starting with its root
    Code adapted from https://stackoverflow.com/questions/35920826/how-to-find-height-for-non-binary-tree
    :param root: spacy.tokens.token.Token
    :return: int, maximum height of sentence's dependency parse tree
    """
    if not list(root.children):
        return 1
    else:
        return 1 + max(tree_height(x) for x in root.children)


def get_average_heights(paragraph):
    """
    Computes average height of parse trees for each sentence in paragraph.
    :param paragraph: spacy doc object or str
    :return: float
    """
    if type(paragraph) == str:
        doc = nlp(paragraph)
    else:
        doc = paragraph
    roots = [sent.root for sent in doc.sents]
    return np.mean([tree_height(root) for root in roots])


def test_average_height_func():
    paragraph = (u"Autonomous cars shift insurance liability toward manufacturers. Consumers rejoice."
                 " Manufacturers complain a lot. Suffer.")
    paragraph2 = (u"The cat on the hot tin roof of my parent's house meowed.")
    paragraph3 = (u"The cat on the hot tin roof meowed at my parent's house.")

    print(paragraph)
    print(get_average_heights(paragraph))

    print(paragraph2)
    print(get_average_heights(paragraph2))

    print(paragraph3)
    print(get_average_heights(paragraph3))


if __name__ == "__main__":
    test_average_height_func()