NLTK python error: "TypeError: 'dict_keys' object is not subscriptable"

Question:

I am following instructions for a class homework assignment and I am supposed to look up the top 200 most frequently used words in a text file.

Here’s the last part of the code:

fdist1 = FreqDist(NSmyText)
vocab=fdist1.keys()
vocab[:200]

But when I press enter after the vocab 200 line, it returns:

 Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
TypeError: 'dict_keys' object is not subscriptable

Any suggestions on how to fix this so it can correctly return an answer?

Asked By: user3760644

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Source

Answers:

Looks like you are using Python 3. In Python 3 dict.keys() returns an iterable but not indexable object. The most simple (but not so efficient) solution would be:

vocab = list(fdist1.keys())[:200]

In some situations it is desirable to continue working with an iterator object instead of a list. This can be done with itertools.islice():

import itertools
vocal_iterator = itertools.islice(fdist1.keys(), 200)
Answered By: Klaus D.

To print the most frequently used 200 words use:
fdist1.most_common(200)
The above line of code will return the 200 most frequently used words as key-frequency pair.

Answered By: Shikhar Gupta

If your using python 3 try: 

fdist1.most_common(200)

instead, to get the 200 most frequent words.

Answered By: lasu moses

I am using python 3.5 and I meet the same problem of TypeError.

Using vocab = list(fdist1.keys()) does not give me the top 50 most frequently used words.
But fdist1.most_common(50) does.

Further,if you just want to show those top 50 words not with their frequency,you can try :

[word for (word, freq) in fdist1.most_common(50)]

Answered By: Roy Chen

fdist1 = FreqDist(NSmyText)

vocab=fdist1.keys()

This code is using in Python2.7.
So you should do some change.
dic.keys() returns an iteratable. So using:

list(fdist1.keys())

Answered By: Heron

If you want to get elements as keys and values (word and frequency), you can use:

list(fdist1.items())[:200]

Answered By: zarooba