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added idf-smooth (#2174)

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* added idf-smooth

* added idf-smooth

* added idf-smooth
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Shubham Shaswat 2020-09-02 23:03:12 +05:30 committed by GitHub
parent e92e433dbe
commit a1d1a44f51
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1 changed files with 12 additions and 4 deletions
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16
machine_learning/word_frequency_functions.py
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@ -83,16 +83,17 @@ the third document in the corpus.")
return (len([doc for doc in docs if term in doc]), len(docs))
def inverse_document_frequency(df: int, N: int) -> float:
def inverse_document_frequency(df: int, N: int, smoothing=False) -> float:
"""
Return an integer denoting the importance
of a word. This measure of importance is
calculated by log10(N/df), where N is the
number of documents and df is
the Document Frequency.
@params : df, the Document Frequency, and N,
the number of documents in the corpus.
@returns : log10(N/df)
@params : df, the Document Frequency, N,
the number of documents in the corpus and
smoothing, if True return the idf-smooth
@returns : log10(N/df) or 1+log10(N/1+df)
@examples :
>>> inverse_document_frequency(3, 0)
Traceback (most recent call last):
@ -104,7 +105,14 @@ def inverse_document_frequency(df: int, N: int) -> float:
Traceback (most recent call last):
...
ZeroDivisionError: df must be > 0
>>> inverse_document_frequency(0, 3,True)
1.477
"""
if smoothing:
if N == 0:
raise ValueError("log10(0) is undefined.")
return round(1 + log10(N / (1 + df)), 3)
if df == 0:
raise ZeroDivisionError("df must be > 0")
elif N == 0: