You should set min_df=1 and max_df=1.0 (which should be the default, but it depends on your scikit-learn version).
How did you determine that your vocabulary size should be 1860?


On 11/19/2015 12:31 PM, Ehsan Asgari wrote:
Hi,

Thank you for your reply. I changed my delimeters from tab to space and most of the problem has been solved (1900 index term from 1914). However, still there are few words that are excluded. I didn't set any parameter as you can see in the code.

    |tf = TfidfVectorizer(ngram_range=(1,ngram),use_idf=False)
    tf_matrix = tf.fit_transform(corpus) feature_names =
    tf.get_feature_names()|

Should I play with the min_df and max_df?

Best,
Ehsan

On Nov 19, 2015, at 9:01 AM, Chris Holdgraf <choldg...@berkeley.edu <mailto:choldg...@berkeley.edu>> wrote:

If you vocab is indeed being cut down, could it be because some words don't pass through the word frequency cutoff filters? (min_df, max_df)

On Thu, Nov 19, 2015 at 8:55 AM, Andreas Mueller <t3k...@gmail.com <mailto:t3k...@gmail.com>> wrote:

    Hi Ehsan.
    Which version of scikit-learn are you using?
    And why do you think the vocabulary size is 1860?
    What is len(tf.vocabulary_)?

    Andy

    On 11/18/2015 11:45 PM, Ehsan Asgari wrote:

    Hi,

    I am using TfidfVectorizer of sklearn.feature_extraction.text
    for generating tf-idf matrix of a corpus. However, when I look
    at the features extracted from my corpus it seems that it has
    reduced my vocabulary size from 1860 to 598! I tried to play
    with max_df, min_df, and max_features. But nothing changed.

    |tf = TfidfVectorizer(ngram_range=(1,ngram),use_idf=False)
    tf_matrix = tf.fit_transform(corpus) feature_names =
    tf.get_feature_names() |

    Does someone have an idea how to solve this problem?

    Thank you,

    Ehsan




    
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