addEntityDetails

Add entity tags to documents

Use addEntityDetails to add entity tags to documents.

Use addEntityDetails to detect person names, locations, organizations, and other named entities in text. This process is known as named entity recognition.

The function supports English, Japanese, and German text.

Syntax

updatedDocuments = addEntityDetails(documents)
updatedDocuments = addEntityDetails(documents,'RetokenizeMethod',method)

Description

example

updatedDocuments = addEntityDetails(documents) detects the named entities in documents. The function adds details to the tokens with missing entity details only. To get the entity details from updatedDocuments, use tokenDetails.

updatedDocuments = addEntityDetails(documents,'RetokenizeMethod',method) also specifies the method to retokenize the documents.

Tip

Use addEntityDetails before using the lower, upper, normalizeWords, removeWords, and removeStopWords functions as addEntityDetails uses information that is removed by these functions.

Examples

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Create a tokenized document array.

str = [
    "Mary moved to Natick, Massachusetts."
    "John uses MATLAB at MathWorks."];
documents = tokenizedDocument(str);

Add the entity details to the documents using the addEntityDetails function. This function detects the named entities in the text and adds the details to the table returned by the tokenDetails function. View the updated token details of the first few tokens.

documents = addEntityDetails(documents);
tdetails = tokenDetails(documents)
tdetails=13×8 table
         Token         DocumentNumber    SentenceNumber    LineNumber       Type        Language    PartOfSpeech       Entity   
    _______________    ______________    ______________    __________    ___________    ________    ____________    ____________

    "Mary"                   1                 1               1         letters           en       proper-noun     person      
    "moved"                  1                 1               1         letters           en       verb            non-entity  
    "to"                     1                 1               1         letters           en       adposition      non-entity  
    "Natick"                 1                 1               1         letters           en       proper-noun     location    
    ","                      1                 1               1         punctuation       en       punctuation     non-entity  
    "Massachusetts"          1                 1               1         letters           en       proper-noun     location    
    "."                      1                 1               1         punctuation       en       punctuation     non-entity  
    "John"                   2                 1               1         letters           en       proper-noun     person      
    "uses"                   2                 1               1         letters           en       verb            non-entity  
    "MATLAB"                 2                 1               1         letters           en       proper-noun     other       
    "at"                     2                 1               1         letters           en       adposition      non-entity  
    "MathWorks"              2                 1               1         letters           en       proper-noun     organization
    "."                      2                 1               1         punctuation       en       punctuation     non-entity  

View the words tagged with the entities "person", "location", "organization", or "other". These words are the words not tagged with "non-entity".

idx = tdetails.Entity ~= "non-entity";
tdetails.Token(idx)
ans = 6×1 string array
    "Mary"
    "Natick"
    "Massachusetts"
    "John"
    "MATLAB"
    "MathWorks"

Tokenize Japanese text using tokenizedDocument.

str = [
    "マリーさんはボストンからニューヨークに引っ越しました。"
    "駅で鈴木さんに迎えに行きます。"
    "東京は大阪より大きいですか?"
    "東京に行った時、新宿や渋谷などいろいろな所に訪れたました。"];
documents = tokenizedDocument(str);

For Japanese text, the software automatically adds named entity tags, so you do not need to use the addEntityDetails function. This software detects person names, locations, organizations, and other named entities. To view the entity details, use the tokenDetails function.

tdetails = tokenDetails(documents);
head(tdetails)
ans=8×8 table
       Token        DocumentNumber    LineNumber     Type      Language    PartOfSpeech       Lemma          Entity  
    ____________    ______________    __________    _______    ________    ____________    ____________    __________

    "マリー"               1               1         letters       ja       proper-noun     "マリー"         person    
    "さん"                1               1         letters       ja       noun            "さん"           person    
    "は"                  1               1         letters       ja       adposition      "は"            non-entity
    "ボストン"             1               1         letters       ja       proper-noun     "ボストン"        location  
    "から"                1               1         letters       ja       adposition      "から"           non-entity
    "ニューヨーク"          1               1         letters       ja       proper-noun     "ニューヨーク"    location  
    "に"                  1               1         letters       ja       adposition      "に"            non-entity
    "引っ越し"             1               1         letters       ja       verb            "引っ越す"        non-entity

View the words tagged with entity "person", "location", "organization", or "other". These words are the words not tagged "non-entity".

idx = tdetails.Entity ~= "non-entity";
tdetails(idx,:).Token
ans = 11×1 string array
    "マリー"
    "さん"
    "ボストン"
    "ニューヨーク"
    "鈴木"
    "さん"
    "東京"
    "大阪"
    "東京"
    "新宿"
    "渋谷"

Tokenize German text using tokenizedDocument.

str = [
    "Ernst zog von Frankfurt nach Berlin."
    "Besuchen Sie Volkswagen in Wolfsburg."];
documents = tokenizedDocument(str);

To add entity tags to German text, use the addEntityDetails function. This function detects person names, locations, organizations, and other named entities.

documents = addEntityDetails(documents);

To view the entity details, use the tokenDetails function.

tdetails = tokenDetails(documents);
head(tdetails)
ans=8×8 table
       Token       DocumentNumber    SentenceNumber    LineNumber       Type        Language    PartOfSpeech      Entity  
    ___________    ______________    ______________    __________    ___________    ________    ____________    __________

    "Ernst"              1                 1               1         letters           de       proper-noun     person    
    "zog"                1                 1               1         letters           de       verb            non-entity
    "von"                1                 1               1         letters           de       adposition      non-entity
    "Frankfurt"          1                 1               1         letters           de       proper-noun     location  
    "nach"               1                 1               1         letters           de       adposition      non-entity
    "Berlin"             1                 1               1         letters           de       proper-noun     location  
    "."                  1                 1               1         punctuation       de       punctuation     non-entity
    "Besuchen"           2                 1               1         letters           de       verb            non-entity

View the words tagged with entity "person", "location", "organization", or "other". These words are the words not tagged with "non-entity".

idx = tdetails.Entity ~= "non-entity";
tdetails(idx,:)
ans=5×8 table
       Token        DocumentNumber    SentenceNumber    LineNumber     Type      Language    PartOfSpeech       Entity   
    ____________    ______________    ______________    __________    _______    ________    ____________    ____________

    "Ernst"               1                 1               1         letters       de       proper-noun     person      
    "Frankfurt"           1                 1               1         letters       de       proper-noun     location    
    "Berlin"              1                 1               1         letters       de       proper-noun     location    
    "Volkswagen"          2                 1               1         letters       de       noun            organization
    "Wolfsburg"           2                 1               1         letters       de       proper-noun     location    

Input Arguments

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Input documents, specified as a tokenizedDocument array.

Method to retokenize documents, specified as one of the following:

  • 'entity' – Transform the tokens for named entity recognition. The function merges tokens from the same entity into a single token.

  • 'none' – Do not retokenize the documents.

Output Arguments

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Updated documents, returned as a tokenizedDocument array. To get the token details from updatedDocuments, use tokenDetails.

Algorithms

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Language Details

tokenizedDocument objects contain details about the tokens including language details. The language details of the input documents determine the behavior of addEntityDetails. The tokenizedDocument function, by default, automatically detects the language of the input text. To specify the language details manually, use the 'Language' name-value pair argument of tokenizedDocument. To view the token details, use the tokenDetails function.

Introduced in R2019a