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TypeError: unhashable type: 'dict'
This error indicates that you're attempting to use a dictionary as a key in a dictionary or set. Dicts, by default, cannot be hashed, and thus cannot be used as keys.
Solution:
To resolve this issue, you can freeze the dictionary using frozenset, which creates a hashable representation of the dictionary. Immutability is critical because only immutable objects (like strings, numbers, and tuples) can be hashed.
Example:
Consider this code:
<code class="python">movie_reviews = ... negids = movie_reviews.fileids('neg') def word_feats(words): return dict([(word, True) for word in words]) # Constructing a list of tuples instead of dicts for hashability negfeats = [(word_feats(movie_reviews.words(fileids=[f])), 'neg') for f in negids] stopset = set(stopwords.words('english')) def stopword_filtered_word_feats(words): return dict([(word, True) for word in words if word not in stopset]) # Use frozenset to freeze the key (dict) of the nested dictionary result = {frozenset(key.items()): value for key, value in negfeats}</code>
In this example, the negfeats list is constructed with tuples instead of dictionaries to ensure hashability. Additionally, the stopword_filtered_word_feats function returns a different dictionary structure than the original code, where the keys are frozen sets of tuples. This structure is hashable and compatible with the updated code.
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