NLTK POS tagger not working

Question

If I try this :

import nltk
text = nltk.word_tokenize("And now for something completely different")
nltk.pos_tag(text)

Output:

Traceback (most recent call last):
File "C:/Python27/pos.py", line 3, in <module>
nltk.pos_tag(text)
File "C:\Python27\lib\site-packages\nltk-2.0.4-py2.7.egg\nltk\tag\__init__.py" ipos_tag
tagger = load(_POS_TAGGER)
File "C:\Python27\lib\site-packages\nltk-2.0.4-py2.7.egg\nltk\data.py", line 605,in 
resource_val = pickle.load(_open(resource_url))
ImportError: No module named numpy.core.multiarray

Stopgap

Answer 1

It seems that the saved word tokenizer requires numpy. You'll need to install it.

Storer

If Numpy's required by NLTK, shouldn't it be installed as a dependency automatically assuming one used Pip or other installer tools? I ask because I installed NLTK using Pip, then encountered the same issue. – Guillot

@Guillot Numpy's not required for most of NLTK, just some parts. (It's listed as optional on the install page.) That said, it's super-handy to have around in general if you're doing any kind of machine learning type stuff or other number crunching. – Storer

wouldn't it be better for NLTK to split out the numpy-dependent code to a separate library – Lit

Answer 2

Install numpy using the command:

sudo pip install -U numpy

Stroll