我正在学习 NLTK，我的 mac 工作正常，除了 FreqDist() 有问题。（我看到另一个关于 FreqDist() 的问题，但他收到了不同的错误消息。TypeError: unhashable type: 'list'）这是一个例子：
>>> from nltk.corpus import brown
>>> news_text = brown.words(categories='news')
>>> fdist = nltk.FreqDist([w.lower() for w in news_text])
Traceback (most recent call last):
` File "<stdin>", line 1, in <module>`
`NameError: name 'nltk' is not defined`
此错误消息非常一致。每次尝试 FreqDist() 时都会收到此消息。其他命令，如 - >>> brown.fileids() 很好。
谢谢你的帮助！
在您可以使用 FreqDist 之前，您需要将其导入。
添加一行如下：
import nltk
或者如果你只是想使用 FreqDist 你应该试试这个：
>>> from nltk.corpus import brown
>>> from nltk import FreqDist
>>> news_text = brown.words(categories='news')
>>> fdist = FreqDist([w.lower() for w in news_text])
which means you haven't installed nltk. follow these steps to install nltk:
1:go to this link https://pypi.python.org/pypi/setuptools at the end of page you find setuptools-7.0.zip (md5) download it, then unzip it. you can find easy_install.py python script.
2:use the command sudo easy_install pip. By this time pip will be installed ready to use, (make sure you are in the directory where you can find easy_install script file).
3:use this command sudo pip install -U nltk. successful execution ensure that nltk is now installed.
4:open the IDLE then you type the following:
import nltk
if nltk is installed properly then you will be returned with console.
nltk 需要您首先下载的数据。然后运行以下代码：
import nltk
nltk.download('stopwords')
from nltk.corpus import stopwords
stopwords.words("english")
旧版本的 Python 需要 setuptools。如果您运行的是 3.2+，则不需要相同的内容您可以从https://pypi.python.org/pypi/nltk轻松下载相同内容