AttributeError：“列表”对象没有属性“ isdigit”

Question

I want to extract POS in pandas. I do as below

import pandas as pd
from nltk.tag import pos_tag
df = pd.DataFrame({'pos': ['noun', 'Alice', 'good', 'well', 'city']})
s = df['pos']
tagged_sent = pos_tag(s.str.split())

but get a traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "../lib/python2.7/site-packages/nltk/tag/__init__.py", line 111, in pos_tag
    return _pos_tag(tokens, tagset, tagger)
  File "../lib/python2.7/site-packages/nltk/tag/__init__.py", line 82, in _pos_tag
    tagged_tokens = tagger.tag(tokens)
  File "/Users/mjpieters/Development/venvs/stackoverflow-2.7/lib/python2.7/site-packages/nltk/tag/perceptron.py", line 152, in tag
    context = self.START + [self.normalize(w) for w in tokens] + self.END
  File "../lib/python2.7/site-packages/nltk/tag/perceptron.py", line 224, in normalize
    elif word.isdigit() and len(word) == 4:
AttributeError: 'list' object has no attribute 'isdigit'

What's wrong?

Answer 1

You can actually pass Series object to the pos_tag() method directly:

s = df['pos']
tagged_sent = pos_tag(s)  # or pos_tag(s.tolist())
print(tagged_sent)

Prints:

[('noun', 'JJ'), ('Alice', 'NNP'), ('good', 'JJ'), ('well', 'RB'), ('city', 'NN')]

Answer 2

表达式s.str.split()是一个字符串list ，而不是字符串（由pos_tag期望。），因为isdigit是str一种方法。