Here are a few title options, focusing on the core issue and solution: Direct and Informative: * TypeError: \"unhashable type: \'dict\'\" - How to Make Dictionaries Hashable in Python * Py

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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