Comments on: Part of Speech Tagging with NLTK Part 1 – Ngram Taggers

By: VasilisG

VasilisG — Sun, 08 Apr 2012 19:55:00 +0000

Hi Jacob, when I try to create the ubt I receive the following error:

Traceback (most recent call last):
File “”, line 1, in
    ubt_tagger = backoff_tagger(train_sents, [nltk.tag.UnigramTagger, nltk.tag.BigramTagger, nltk.tag.TrigramTagger])
File “”, line 3, in backoff_tagger
    backoff = tagger_classes[0](tagged_sents)
File “/usr/local/lib/python2.6/dist-packages/nltk/tag/sequential.py”, line 317, in __init__
    backoff, cutoff, verbose)
File “/usr/local/lib/python2.6/dist-packages/nltk/tag/sequential.py”, line 274, in __init__
    self._train(train, cutoff, verbose)
File “/usr/local/lib/python2.6/dist-packages/nltk/tag/sequential.py”, line 177, in _train
    tokens, tags = zip(*sentence)
ValueError: need more than 1 value to unpack

Is it because some change in NLTK’s API?

Thanks,
Vasilis

By: Xiejuncs

Xiejuncs — Wed, 12 Jan 2011 06:15:00 +0000

I also have the same question on which algorithm pos_tag method employ. Thank you very much…

By: Jacob Perkins

Jacob Perkins — Thu, 06 Jan 2011 16:37:00 +0000

Thanks Martin.

nltk.pos_tag uses a ClassifierBasedTagger trained on treebank. Presumably it uses at least the same features as ClassifierBasedPOSTagger, but when I tested my own ClassifierBasedPOSTagger against nltk.pos_tag, nltk.pos_tag was a bit more accurate on treebank.

By: M D Sykora

M D Sykora — Thu, 06 Jan 2011 16:24:00 +0000

Excellent post, on tagging and the entire blog, I love it, since it’s a good read and you write on interesting topics.

One question thought, what method/algorithm does the nltk.pos_tag(..) use in the background. I’ve used this NLTK out of the box :

text = nltk.word_tokenize(“Some normal and common English language text, that needs to be part of speech tagged.”)

nltk.pos_tag(text)

Thanks,
Martin

By: Learning to do natural language processing with NLTK | JetLlib Journal

Learning to do natural language processing with NLTK | JetLlib Journal — Sat, 03 Apr 2010 20:11:48 +0000

[...] of Speech Tagging with NLTK – Part 1, Part 2, Part [...]

By: Jacob

Jacob — Thu, 08 Oct 2009 02:47:48 +0000

Moses: The wordpress plugin is SyntaxHighlighter Evolved http://www.viper007bond.com/wordpress-plugins/syntaxhighlighter/

By: Moses

Moses — Thu, 08 Oct 2009 02:07:38 +0000

Would you mind telling me what editor you were using for the codes above? it’s pretty cool

By: Andrew Lee

Andrew Lee — Wed, 25 Mar 2009 18:23:59 +0000

Thank you!

By: Jacob

Jacob — Wed, 25 Mar 2009 14:04:56 +0000

The NLTK corpus API has changed since I wrote this. Try with categories=['reviews']

By: Andrew Lee

Andrew Lee — Wed, 25 Mar 2009 08:38:31 +0000

for nltk version 0.9.9b1 the call to taged_sents in

nltk.corpus.brown.tagged_sents(categories=”c”)

Throws the error:

Traceback (most recent call last):
File “”, line 2, in ?
File “/usr/lib/python2.4/site-packages/nltk/corpus/reader/tagged.py”, line 211, in tagged_sents
return TaggedCorpusReader.tagged_sents(
File “/usr/lib/python2.4/site-packages/nltk/corpus/reader/tagged.py”, line 148, in tagged_sents
tag_mapping_function)
File “/usr/lib/python2.4/site-packages/nltk/corpus/reader/util.py”, line 409, in concat
raise ValueError(‘concat() expects at least one object!’)
ValueError: concat() expects at least one object!