scikit-learn how to know documents in the cluster?

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没有蜡笔的小新
没有蜡笔的小新 2020-12-28 10:58

I am new to both python and scikit-learn so please bear with me.

I took this source code for k means clustering algorithm from k means clustering.

I then modif

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  •  旧时难觅i
    2020-12-28 11:46

    Forget about the Bunch object. It's just an implementation detail to load the toy datasets that are bundled with scikit-learn.

    In real life, with you real data you just have to call directly:

    km = KMeans(n_clusters).fit(my_document_features)
    

    then collect cluster assignments from:

    km.labels_
    

    my_document_features is a 2D datastructure: either a numpy array or a scipy.sparse matrix with shape (n_documents, n_features).

    km.labels_ is a 1D numpy array with shape (n_documents,). Hence the first element in labels_ is the index of the cluster of the document described in the first row of the my_document_features feature matrix.

    Typically you would build my_document_features with a TfidfVectorizer object:

    my_document_features = TfidfVectorizer().fit_transform(my_text_documents)
    

    and my_text_documents would a either a list python unicode objects if you read the documents directly (e.g. from a database or rows from a single CSV file or whatever you want) or alternatively:

    vec = TfidfVectorizer(input='filename')
    my_document_features = vec.fit_transform(my_text_files)
    

    where my_text_files is a python list of the path of your document files on your harddrive (assuming they are encoded using the UTF-8 encoding).

    The length of the my_text_files or my_text_documents lists should be n_documents hence the mapping with km.labels_ is direct.

    As scikit-learn is not just for clustering or categorizing documents, we use the name "sample" instead of "document". This is way you will see the we use n_samples instead of n_documents to document the expected shapes of the arguments and attributes of all the estimator in the library.

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