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encode

Encode documents as matrix of word or n-gram counts

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Syntax

计数= encode(bag,documents)
计数= encode(bag,words)
计数= encode(___,Name,Value)

Description

Useencode编码一组标记化的文档作为一个垫子上rix of word or n-gram counts according to a bag-of-words or bag-of-n-grams model. To encode documents as vectors or word indices, use awordEncodingobject.

example

计数= encode(袋,documents)returns a matrix of frequency counts fordocumentsbased on the bag-of-words or bag-of-n-grams model袋.

example

计数= encode(袋,words)returns a matrix of frequency counts for a list of words.

example

计数= encode(___,Name,Value)specifies additional options using one or more name-value pair arguments.

Examples

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Open Live Script

Encode an array of documents as a matrix of word counts.

documents = tokenizedDocument(["an example of a short sentence""a second short sentence"]); bag = bagOfWords(documents)
袋= bagOfWords with properties: Counts: [2x7 double] Vocabulary: ["an" "example" "of" "a" "short" ... ] NumWords: 7 NumDocuments: 2
documents = tokenizedDocument(["a new sentence""a second new sentence"])
documents = 2x1 tokenizedDocument: 3 tokens: a new sentence 4 tokens: a second new sentence

View the documents encoded as a matrix of word counts. The word "new" does not appear in袋, so it is not counted.

计数= encode(bag,documents); full(counts)
ans =2×70 0 0 1 0 1 0 0 0 0 1 0 1 1

The columns correspond to the vocabulary of the bag-of-words model.

袋.Vocabulary
ans =1x7 string"an" "example" "of" "a" "short" "sentence" "second"
Open Live Script

Encode an array of words as a vector of word counts.

documents = tokenizedDocument(["an example of a short sentence""a second short sentence"]); bag = bagOfWords(documents)
袋= bagOfWords with properties: Counts: [2x7 double] Vocabulary: ["an" "example" "of" "a" "short" ... ] NumWords: 7 NumDocuments: 2
words = ["another""example""of""a""short""example""sentence"]; counts = encode(bag,words)
计数= (1,2) 2 (1,3) 1 (1,4) 1 (1,5) 1 (1,6) 1
Open Live Script

Encode an array of documents as a matrix of word counts with documents in columns.

documents = tokenizedDocument(["an example of a short sentence""a second short sentence"]); bag = bagOfWords(documents)
袋= bagOfWords with properties: Counts: [2x7 double] Vocabulary: ["an" "example" "of" "a" "short" ... ] NumWords: 7 NumDocuments: 2
documents = tokenizedDocument(["a new sentence""a second new sentence"])
documents = 2x1 tokenizedDocument: 3 tokens: a new sentence 4 tokens: a second new sentence

View the documents encoded as a matrix of word counts with documents in columns. The word "new" does not appear in袋, so it is not counted.

计数= encode(bag,documents,'DocumentsIn','columns'); full(counts)
ans =7×20 0 0 0 0 0 1 1 0 0 1 1 0 1

Input Arguments

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Input bag-of-words or bag-of-n-grams model, specified as a袋OfWordsobject or a袋OfNgramsobject.

Input documents, specified as atokenizedDocumentarray, a string array of words, or a cell array of character vectors. Ifdocumentsis a string array or a cell array of character vectors, then it must be a row vector representing a single document, where each element is a word.

Tip

To ensure that the documents are encoded correctly, you must preprocess the input documents using the same steps as the documents used to create the input model. For an example showing how to create a function to preprocess text data, seePrepare Text Data for Analysis.

Input words, specified as a string vector, character vector, or cell array of character vectors. If you specifywordsas a character vector, then the function treats the argument as a single word.

Data Types:string|char|cell

Name-Value Arguments

Specify optional pairs of arguments asName1=Value1,...,NameN=ValueN, whereNameis the argument name andValueis the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and encloseNamein quotes.

Example:'DocumentsIn','rows'specifies the orientation of the output documents as rows.

Orientation of output documents in the frequency count matrix, specified as the comma-separated pair consisting of'DocumentsIn'and one of the following:

  • 'rows'– Return a matrix of frequency counts with rows corresponding to documents.

  • 'columns'– Return a transposed matrix of frequency counts with columns corresponding to documents.

Data Types:char

Indicator for forcing output to be returned as cell array, specified as the comma separated pair consisting of'ForceCellOutput'andtrueorfalse.

Data Types:logical

Output Arguments

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Word or n-gram counts, returned as a sparse matrix of nonnegative integers or a cell array of sparse matrices.

If袋is a non-scalar array or'ForceCellOutput'istrue, then the function returns the outputs as a cell array of sparse matrices. Each element in the cell array is matrix of word or n-gram counts of the corresponding element of袋.

Version History

Introduced in R2017b

See Also

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