To understand inverse document frequency, first we need to understand document frequency
Document Frequency is the number of documents in which the word occurs irrespective of how many times it has occurred in those documents
In the case of inverse document frequency, we need to put the document frequency in the denominator while the total number of documents is the numerator. For example, if the document frequency of the word “AMAN” is 2 in a particular document then its inverse document frequency will be 3/2. (Here no. of documents is 3)
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