Unexpected behaviour when creating dependency lables from array as according the tutorial at http://spacy.io/docs/tutorials/byo-annotations.

unexpected_from_array.py

# Python 3
# coding: utf-8

import spacy
from spacy.attrs import HEAD, DEP
from spacy.symbols import nsubj, root, dobj, punct
from numpy import ndarray

nlp = spacy.load('en')

doc = nlp('I eat apples.', parse=False)

columns = [HEAD, DEP]
values = ndarray(shape=(len(columns), len(doc)), dtype='int32')
# Syntactic parse specified as head offsets
heads = [1,1,1,1]
# Integer IDs for the dependency labels. See the parse in the displaCy
# demo at spacy.io/demos/displacy
labels = [nsubj, root, dobj, punct]
values[0] = heads
values[1] = labels
doc.from_array(columns, values)

print([t.dep_ for t in doc])
print([t.dep for t in doc])
print(values)
#print([t.head for t in doc])    # This raises an index error.