I'm try to tag a single word with the nltk pos tagger:
word = "going"
pos = nltk.pos_tag(word)
print pos
But the output is this:
[('g', 'NN'), ('o', 'VBD'), ('i', 'PRP'), ('n', 'VBP'), ('g', 'JJ')]
It's tagging each letter rather than just the one word.
What can I do to make it tag the word?
nltk.tag.pos_tag accepts a list of tokens, separate and tags its elements. Therefore you need to put your words in an iterable like list:
>>> nltk.tag.pos_tag(['going'])
[('going', 'VBG')]
>>> word = 'going'
>>> word = nltk.word_tokenize(word)
>>> l1 = nltk.pos_tag(word)
>>> l1
[('going', 'VBG')]
The tagger works on a list of words. To turn the string into a list simply use something like
word_list = [word]
then use the pos tagger on the word_list. Note that if you have more than one word, you should run nltk.word_tokenize on the string first.
As for the success in tagging only one word, you should look into the lookup tagger mentioned in section 4.3 here. The pos_tag used by nltk is more complicated than just a one word lookup tagger, but it does use one as part of the process, so you should see ok results.
来源：https://stackoverflow.com/questions/29397708/tagging-a-single-word-with-the-nltk-pos-tagger-tags-each-letter-instead-of-the-w