Frequency is a measure of how often a term appears in a document. The terms can be single words, phrases, or even longer strings of text. The frequency of a term can be used to provide insight into the overall topic of a document or to help identify important terms within the document.
Query Document and Frequency
When you perform a search query, the frequency of each term in your query is compared to the frequencies of those same terms in the documents in the search index. The more frequently a term appears in a document, the more relevant that document is considered to be for your query.
You can also use frequency to compare different documents to see how similar they are. The greater the overlap in terms between two documents, the more similar they are considered to be.
Frequency can also be used as a measure of importance. The more often a term appears in a document, the more important it is considered to be. This can be helpful when trying to identify key terms within a document.
TF-IDF (term frequency-inverse document frequency)
TF-IDF is a statistical measure that is used to weigh the importance of terms in a document. The importance of a term is measured by its frequency in a document, and its inverse document frequency. Inverse document frequency is a measure of how uncommon a term is across all documents. Terms with a high TF-IDF are considered to be important terms for that particular document.
Analyzing Word Frequency
One of the most common ways to analyze word frequency is through a process called stemming. Stemming is the process of reducing a word to its base form. For example, the word “stems” would be reduced to “stem”. This can be helpful when you are looking at a large document and want to reduce the number of unique terms.
When you stem a term, you can also create a new term that is related to the original term. For example, if you stem the word “computer”, you could create the new term “computational”. This new term would be considered to be related to the original term, but not identical.
Another way to analyze word frequency is to look at the co-occurrence of terms. Co-occurrence is the measure of how often two terms appear in close proximity to each other. This can be helpful in identifying relationships between terms.
There are many other ways to measure and analyze word frequency. These are just a few of the most common methods.