Train_naive_bayes

Course Q&A Natural Language Processing NLP with Classification and Vector Spaces
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Hi,
I’m getting this error when testing my function train_naive_bayes

屏幕截图 2022-06-28 014156
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I have already got the expected output.
My labID is aashcwtc

Thank you!

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Usually, a sanity test is shown in the notebook along with the expected values. The test_<method> contains more test cases. Please checking your implementation. Should you feel it’s right, click my name and message your notebook as an attachment.

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Here are a couple of hints for you to fix train_naive_bayes:

  1. When computing N_pos and N_neg, don’t add 1 to increment the count. This comment should help # Increment the number of positive words by the count for this (word, label) pair.
  2. When computing freq_pos and freq_neg, you shouldn’t hardcode the word.
1 Like
4

Hi,
Thanks for the response. If i don’t hardcode the word, then I use

for word in vocab:

    freq_pos = freqs[(word,1.0)]
    freq_neg = freqs[(word,0.0)]

But I got an error message saying that there is a KeyError. Can you please help me with this? Thank you.

5

I am assuming that I come accross a word in vocab that does not exist in the dictionary freqs, so it raises a key error? But shouldn’t vocab come from freqs.keys()? I am confused

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There is no guarantee that any given word has both a positive and negative frequency entry in the dictionary. So your code needs to handle that. The cleanest way is to use the “get()” method, but if you like writing more code, you can also use “if” clauses.

1 Like
7

Thank you for the response. After using get(), I’m having this error.

{moderator edit - solution code removed}

I think the problem still exists since for some words, they don’t have both (word,1.0) and (word,0.0) keys, then the get() function will return a “Nonetype” and this raises an error

8

Problem solved by adding “if” clauses, thank you!

9

You’re using “get()” incorrectly. The second argument is the value to be returned when the key is not found. You set that as “None”, which is why you got that error. Try 0. instead and it will work a lot better.

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  1. of this comment helped me after dreaded hours of struggle on the question