Analyzing Sentiment

Sentiment Analysisinspects the given text and identifies the prevailing emotional opinion within the text, especially to determine a writer's attitude as positive, negative, or neutral. Sentiment analysis is performed through the analyzeSentiment method. For information on which languages are supported by the Natural Language API, see Language Support . For information on how to interpret the score and magnitude sentiment values included in the analysis, see Interpreting sentiment analysis values .

This section demonstrates a few ways to detect sentiment in a document. For each document, you must submit a separate request.

Analyzing Sentiment in a String

Here is an example of performing sentiment analysis on a text string sent directly to the Natural Language API:

Protocol

To analyze sentiment in a document, make a POST request to the documents:analyzeSentiment REST method and provide the appropriate request body as shown in the following example.

The example uses the gcloud auth application-default print-access-token command to obtain an access token for a service account set up for the project using the Google Cloud Platform gcloud CLI . For instructions on installing the gcloud CLI, setting up a project with a service account see the Quickstart .

curl  
-X  
POST  
 \ 
  
-H  
 "Authorization: Bearer " 
 $( 
gcloud  
auth  
application-default  
print-access-token ) 
  
 \ 
  
-H  
 "Content-Type: application/json; charset=utf-8" 
  
 \ 
  
--data  
 "{ 
 'encodingType': 'UTF8', 
 'document': { 
 'type': 'PLAIN_TEXT', 
 'content': 'Enjoy your vacation!' 
 } 
 }" 
  
 "https://language.googleapis.com/v2/documents:analyzeSentiment" 

If you don't specify document.language_code , then the language will be automatically detected. For information on which languages are supported by the Natural Language API, see Language Support . See the Document reference documentation for more information on configuring the request body.

If the request is successful, the server returns a 200 OK HTTP status code and the response in JSON format:

{
  "documentSentiment": {
    "magnitude": 0.8,
    "score": 0.8
  },
  "language": "en",
  "sentences": [
    {
      "text": {
        "content": "Enjoy your vacation!",
        "beginOffset": 0
      },
      "sentiment": {
        "magnitude": 0.8,
        "score": 0.8
      }
    }
  ]
}

documentSentiment.score indicates positive sentiment with a value greater than zero, and negative sentiment with a value less than zero.

gcloud

Refer to the analyze-sentiment command for complete details.

To perform sentiment analysis, use the gcloud CLI and use the --content flag to identify the content to analyze:

gcloud ml language analyze-sentiment --content="Enjoy your vacation!"

If the request is successful, the server returns a response in JSON format:

{
  "documentSentiment": {
    "magnitude": 0.8,
    "score": 0.8
  },
  "language": "en",
  "sentences": [
    {
      "text": {
        "content": "Enjoy your vacation!",
        "beginOffset": 0
      },
      "sentiment": {
        "magnitude": 0.8,
        "score": 0.8
      }
    }
  ]
}

documentSentiment.score indicates positive sentiment with a value greater than zero, and negative sentiment with a value less than zero.

Go

To learn how to install and use the client library for Natural Language, see Natural Language client libraries . For more information, see the Natural Language Go API reference documentation .

To authenticate to Natural Language, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

  import 
  
 ( 
  
 "context" 
  
 "fmt" 
  
 "io" 
  
 language 
  
 "cloud.google.com/go/language/apiv2" 
  
 "cloud.google.com/go/language/apiv2/languagepb" 
 ) 
 // analyzeSentiment sends a string of text to the Cloud Natural Language API to 
 // assess the sentiment of the text. 
 func 
  
 analyzeSentiment 
 ( 
 w 
  
 io 
 . 
 Writer 
 , 
  
 text 
  
 string 
 ) 
  
 error 
  
 { 
  
 ctx 
  
 := 
  
 context 
 . 
 Background 
 () 
  
 // Initialize client. 
  
 client 
 , 
  
 err 
  
 := 
  
 language 
 . 
  NewClient 
 
 ( 
 ctx 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 err 
  
 } 
  
 defer 
  
 client 
 . 
  Close 
 
 () 
  
 resp 
 , 
  
 err 
  
 := 
  
 client 
 . 
 AnalyzeSentiment 
 ( 
 ctx 
 , 
  
& languagepb 
 . 
 AnalyzeSentimentRequest 
 { 
  
 Document 
 : 
  
& languagepb 
 . 
 Document 
 { 
  
 Source 
 : 
  
& languagepb 
 . 
 Document_Content 
 { 
  
 Content 
 : 
  
 text 
 , 
  
 }, 
  
 Type 
 : 
  
 languagepb 
 . 
  Document_PLAIN_TEXT 
 
 , 
  
 }, 
  
 EncodingType 
 : 
  
 languagepb 
 . 
  EncodingType_UTF8 
 
 , 
  
 }) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 fmt 
 . 
 Errorf 
 ( 
 "AnalyzeSentiment: %w" 
 , 
  
 err 
 ) 
  
 } 
  
 fmt 
 . 
 Fprintf 
 ( 
 w 
 , 
  
 "Response: %q\n" 
 , 
  
 resp 
 ) 
  
 return 
  
 nil 
 } 
 

Java

To learn how to install and use the client library for Natural Language, see Natural Language client libraries . For more information, see the Natural Language Java API reference documentation .

To authenticate to Natural Language, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

  // Instantiate the Language client com.google.cloud.language.v2.LanguageServiceClient 
 try 
  
 ( 
 LanguageServiceClient 
  
 language 
  
 = 
  
 LanguageServiceClient 
 . 
 create 
 ()) 
  
 { 
  
 Document 
  
 doc 
  
 = 
  
 Document 
 . 
 newBuilder 
 (). 
 setContent 
 ( 
 text 
 ). 
 setType 
 ( 
 Type 
 . 
 PLAIN_TEXT 
 ). 
 build 
 (); 
  
 AnalyzeSentimentResponse 
  
 response 
  
 = 
  
 language 
 . 
 analyzeSentiment 
 ( 
 doc 
 ); 
  
 Sentiment 
  
 sentiment 
  
 = 
  
 response 
 . 
 getDocumentSentiment 
 (); 
  
 if 
  
 ( 
 sentiment 
  
 == 
  
 null 
 ) 
  
 { 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "No sentiment found" 
 ); 
  
 } 
  
 else 
  
 { 
  
 System 
 . 
 out 
 . 
 printf 
 ( 
 "Sentiment magnitude: %.3f\n" 
 , 
  
 sentiment 
 . 
 getMagnitude 
 ()); 
  
 System 
 . 
 out 
 . 
 printf 
 ( 
 "Sentiment score: %.3f\n" 
 , 
  
 sentiment 
 . 
 getScore 
 ()); 
  
 } 
  
 return 
  
 sentiment 
 ; 
 } 
 

Python

To learn how to install and use the client library for Natural Language, see Natural Language client libraries . For more information, see the Natural Language Python API reference documentation .

To authenticate to Natural Language, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

  from 
  
 google.cloud 
  
 import 
 language_v2 
 def 
  
 sample_analyze_sentiment 
 ( 
 text_content 
 : 
 str 
 = 
 "I am so happy and joyful." 
 ) 
 - 
> None 
 : 
  
 """ 
 Analyzes Sentiment in a string. 
 Args: 
 text_content: The text content to analyze. 
 """ 
 client 
 = 
 language_v2 
 . 
 LanguageServiceClient 
 () 
 # text_content = 'I am so happy and joyful.' 
 # Available types: PLAIN_TEXT, HTML 
 document_type_in_plain_text 
 = 
 language_v2 
 . 
 Document 
 . 
 Type 
 . 
 PLAIN_TEXT 
 # Optional. If not specified, the language is automatically detected. 
 # For list of supported languages: 
 # https://cloud.google.com/natural-language/docs/languages 
 language_code 
 = 
 "en" 
 document 
 = 
 { 
 "content" 
 : 
 text_content 
 , 
 "type_" 
 : 
 document_type_in_plain_text 
 , 
 "language_code" 
 : 
 language_code 
 , 
 } 
 # Available values: NONE, UTF8, UTF16, UTF32 
 # See https://cloud.google.com/natural-language/docs/reference/rest/v2/EncodingType. 
 encoding_type 
 = 
 language_v2 
 . 
 EncodingType 
 . 
 UTF8 
 response 
 = 
 client 
 . 
  analyze_sentiment 
 
 ( 
 request 
 = 
 { 
 "document" 
 : 
 document 
 , 
 "encoding_type" 
 : 
 encoding_type 
 } 
 ) 
 # Get overall sentiment of the input document 
 print 
 ( 
 f 
 "Document sentiment score: 
 { 
 response 
 . 
 document_sentiment 
 . 
 score 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "Document sentiment magnitude: 
 { 
 response 
 . 
 document_sentiment 
 . 
 magnitude 
 } 
 " 
 ) 
 # Get sentiment for all sentences in the document 
 for 
 sentence 
 in 
 response 
 . 
 sentences 
 : 
 print 
 ( 
 f 
 "Sentence text: 
 { 
 sentence 
 . 
 text 
 . 
 content 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "Sentence sentiment score: 
 { 
 sentence 
 . 
 sentiment 
 . 
 score 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "Sentence sentiment magnitude: 
 { 
 sentence 
 . 
 sentiment 
 . 
 magnitude 
 } 
 " 
 ) 
 # Get the language of the text, which will be the same as 
 # the language specified in the request or, if not specified, 
 # the automatically-detected language. 
 print 
 ( 
 f 
 "Language of the text: 
 { 
 response 
 . 
 language_code 
 } 
 " 
 ) 
 

Additional languages

C#: Please follow the C# setup instructions on the client libraries page and then visit the Natural Language reference documentation for .NET.

PHP: Please follow the PHP setup instructions on the client libraries page and then visit the Natural Language reference documentation for PHP.

Ruby: Please follow the Ruby setup instructions on the client libraries page and then visit the Natural Language reference documentation for Ruby.

Analyzing Sentiment from Cloud Storage

For your convenience, the Natural Language API can perform sentiment analysis directly on a file located in Cloud Storage, without the need to send the contents of the file in the body of your request.

Here is an example of performing sentiment analysis on a file located in Cloud Storage.

Protocol

To analyze sentiment from a document stored in Cloud Storage, make a POST request to the documents:analyzeSentiment REST method and provide the appropriate request body with the path to the document as shown in the following example.

curl  
-X  
POST  
 \ 
  
-H  
 "Authorization: Bearer " 
 $( 
gcloud  
auth  
application-default  
print-access-token ) 
  
 \ 
  
-H  
 "Content-Type: application/json; charset=utf-8" 
  
 \ 
  
--data  
 "{ 
 'document':{ 
 'type':'PLAIN_TEXT', 
 'gcsContentUri':'gs:// <bucket-name> 
/ <object-name> 
' 
 } 
 }" 
  
 "https://language.googleapis.com/v2/documents:analyzeSentiment" 

If you don't specify document.language_code , then the language will be automatically detected. For information on which languages are supported by the Natural Language API, see Language Support . See the Document reference documentation for more information on configuring the request body.

If the request is successful, the server returns a 200 OK HTTP status code and the response in JSON format:

{
  "documentSentiment": {
    "magnitude": 0.8,
    "score": 0.8
  },
  "language_code": "en",
  "sentences": [
    {
      "text": {
        "content": "Enjoy your vacation!",
        "beginOffset": 0
      },
      "sentiment": {
        "magnitude": 0.8,
        "score": 0.8
      }
    }
  ]
}

documentSentiment.score indicates positive sentiment with a value greater than zero, and negative sentiment with a value less than zero.

gcloud

Refer to the analyze-sentiment command for complete details.

To perform sentiment analysis on a file in Cloud Storage, use the gcloud command line tool and use the --content-file flag to identify the file path that contains the content to analyze:

gcloud ml language analyze-sentiment --content-file=gs:// YOUR_BUCKET_NAME 
/ YOUR_FILE_NAME 

If the request is successful, the server returns a response in JSON format:

{
  "documentSentiment": {
    "magnitude": 0.8,
    "score": 0.8
  },
  "language": "en",
  "sentences": [
    {
      "text": {
        "content": "Enjoy your vacation!",
        "beginOffset": 0
      },
      "sentiment": {
        "magnitude": 0.8,
        "score": 0.8
      }
    }
  ]
}

documentSentiment.score indicates positive sentiment with a value greater than zero, and negative sentiment with a value less than zero.

Go

To learn how to install and use the client library for Natural Language, see Natural Language client libraries . For more information, see the Natural Language Go API reference documentation .

To authenticate to Natural Language, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

  func 
  
 analyzeSentimentFromGCS 
 ( 
 ctx 
  
 context 
 . 
 Context 
 , 
  
 gcsURI 
  
 string 
 ) 
  
 ( 
 * 
 languagepb 
 . 
 AnalyzeSentimentResponse 
 , 
  
 error 
 ) 
  
 { 
  
 return 
  
 client 
 . 
 AnalyzeSentiment 
 ( 
 ctx 
 , 
  
& languagepb 
 . 
 AnalyzeSentimentRequest 
 { 
  
 Document 
 : 
  
& languagepb 
 . 
 Document 
 { 
  
 Source 
 : 
  
& languagepb 
 . 
 Document_GcsContentUri 
 { 
  
 GcsContentUri 
 : 
  
 gcsURI 
 , 
  
 }, 
  
 Type 
 : 
  
 languagepb 
 . 
 Document_PLAIN_TEXT 
 , 
  
 }, 
  
 }) 
 } 
 

Java

To learn how to install and use the client library for Natural Language, see Natural Language client libraries . For more information, see the Natural Language Java API reference documentation .

To authenticate to Natural Language, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

  // Instantiate the Language client com.google.cloud.language.v2.LanguageServiceClient 
 try 
  
 ( 
 LanguageServiceClient 
  
 language 
  
 = 
  
 LanguageServiceClient 
 . 
 create 
 ()) 
  
 { 
  
 Document 
  
 doc 
  
 = 
  
 Document 
 . 
 newBuilder 
 (). 
 setGcsContentUri 
 ( 
 gcsUri 
 ). 
 setType 
 ( 
 Type 
 . 
 PLAIN_TEXT 
 ). 
 build 
 (); 
  
 AnalyzeSentimentResponse 
  
 response 
  
 = 
  
 language 
 . 
 analyzeSentiment 
 ( 
 doc 
 ); 
  
 Sentiment 
  
 sentiment 
  
 = 
  
 response 
 . 
 getDocumentSentiment 
 (); 
  
 if 
  
 ( 
 sentiment 
  
 == 
  
 null 
 ) 
  
 { 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "No sentiment found" 
 ); 
  
 } 
  
 else 
  
 { 
  
 System 
 . 
 out 
 . 
 printf 
 ( 
 "Sentiment magnitude : %.3f\n" 
 , 
  
 sentiment 
 . 
 getMagnitude 
 ()); 
  
 System 
 . 
 out 
 . 
 printf 
 ( 
 "Sentiment score : %.3f\n" 
 , 
  
 sentiment 
 . 
 getScore 
 ()); 
  
 } 
  
 return 
  
 sentiment 
 ; 
 } 
 

Node.js

To learn how to install and use the client library for Natural Language, see Natural Language client libraries . For more information, see the Natural Language Node.js API reference documentation .

To authenticate to Natural Language, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

  // Imports the Google Cloud client library 
 const 
  
 language 
  
 = 
  
 require 
 ( 
 ' @google-cloud/language 
' 
 ). 
 v2 
 ; 
 // Creates a client 
 const 
  
 client 
  
 = 
  
 new 
  
 language 
 . 
  LanguageServiceClient 
 
 (); 
 /** 
 * TODO(developer): Uncomment the following lines to run this code 
 */ 
 // const bucketName = 'Your bucket name, e.g. my-bucket'; 
 // const fileName = 'Your file name, e.g. my-file.txt'; 
 // Prepares a document, representing a text file in Cloud Storage 
 const 
  
 document 
  
 = 
  
 { 
  
 gcsContentUri 
 : 
  
 `gs:// 
 ${ 
 bucketName 
 } 
 / 
 ${ 
 fileName 
 } 
 ` 
 , 
  
 type 
 : 
  
 'PLAIN_TEXT' 
 , 
 }; 
 // Detects the sentiment of the document 
 const 
  
 [ 
 result 
 ] 
  
 = 
  
 await 
  
 client 
 . 
 analyzeSentiment 
 ({ 
 document 
 }); 
 const 
  
 sentiment 
  
 = 
  
 result 
 . 
 documentSentiment 
 ; 
 console 
 . 
 log 
 ( 
 'Document sentiment:' 
 ); 
 console 
 . 
 log 
 ( 
 `  Score: 
 ${ 
 sentiment 
 . 
 score 
 } 
 ` 
 ); 
 console 
 . 
 log 
 ( 
 `  Magnitude: 
 ${ 
 sentiment 
 . 
 magnitude 
 } 
 ` 
 ); 
 const 
  
 sentences 
  
 = 
  
 result 
 . 
 sentences 
 ; 
 sentences 
 . 
 forEach 
 ( 
 sentence 
  
 = 
>  
 { 
  
 console 
 . 
 log 
 ( 
 `Sentence: 
 ${ 
 sentence 
 . 
 text 
 . 
 content 
 } 
 ` 
 ); 
  
 console 
 . 
 log 
 ( 
 `  Score: 
 ${ 
 sentence 
 . 
 sentiment 
 . 
 score 
 } 
 ` 
 ); 
  
 console 
 . 
 log 
 ( 
 `  Magnitude: 
 ${ 
 sentence 
 . 
 sentiment 
 . 
 magnitude 
 } 
 ` 
 ); 
 }); 
 

Python

To learn how to install and use the client library for Natural Language, see Natural Language client libraries . For more information, see the Natural Language Python API reference documentation .

To authenticate to Natural Language, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

  from 
  
 google.cloud 
  
 import 
 language_v2 
 def 
  
 sample_analyze_sentiment 
 ( 
 gcs_content_uri 
 : 
 str 
 = 
 "gs://cloud-samples-data/language/sentiment-positive.txt" 
 , 
 ) 
 - 
> None 
 : 
  
 """ 
 Analyzes Sentiment in text file stored in Cloud Storage. 
 Args: 
 gcs_content_uri: Google Cloud Storage URI where the file content is located. 
 e.g. gs://[Your Bucket]/[Path to File] 
 """ 
 client 
 = 
 language_v2 
 . 
 LanguageServiceClient 
 () 
 # Available types: PLAIN_TEXT, HTML 
 document_type_in_plain_text 
 = 
 language_v2 
 . 
 Document 
 . 
 Type 
 . 
 PLAIN_TEXT 
 # Optional. If not specified, the language is automatically detected. 
 # For list of supported languages: 
 # https://cloud.google.com/natural-language/docs/languages 
 language_code 
 = 
 "en" 
 document 
 = 
 { 
 "gcs_content_uri" 
 : 
 gcs_content_uri 
 , 
 "type_" 
 : 
 document_type_in_plain_text 
 , 
 "language_code" 
 : 
 language_code 
 , 
 } 
 # Available values: NONE, UTF8, UTF16, UTF32 
 # See https://cloud.google.com/natural-language/docs/reference/rest/v2/EncodingType. 
 encoding_type 
 = 
 language_v2 
 . 
 EncodingType 
 . 
 UTF8 
 response 
 = 
 client 
 . 
  analyze_sentiment 
 
 ( 
 request 
 = 
 { 
 "document" 
 : 
 document 
 , 
 "encoding_type" 
 : 
 encoding_type 
 } 
 ) 
 # Get overall sentiment of the input document 
 print 
 ( 
 f 
 "Document sentiment score: 
 { 
 response 
 . 
 document_sentiment 
 . 
 score 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "Document sentiment magnitude: 
 { 
 response 
 . 
 document_sentiment 
 . 
 magnitude 
 } 
 " 
 ) 
 # Get sentiment for all sentences in the document 
 for 
 sentence 
 in 
 response 
 . 
 sentences 
 : 
 print 
 ( 
 f 
 "Sentence text: 
 { 
 sentence 
 . 
 text 
 . 
 content 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "Sentence sentiment score: 
 { 
 sentence 
 . 
 sentiment 
 . 
 score 
 } 
 " 
 ) 
 print 
 ( 
 f 
 "Sentence sentiment magnitude: 
 { 
 sentence 
 . 
 sentiment 
 . 
 magnitude 
 } 
 " 
 ) 
 # Get the language of the text, which will be the same as 
 # the language specified in the request or, if not specified, 
 # the automatically-detected language. 
 print 
 ( 
 f 
 "Language of the text: 
 { 
 response 
 . 
 language_code 
 } 
 " 
 ) 
 

Additional languages

C#: Please follow the C# setup instructions on the client libraries page and then visit the Natural Language reference documentation for .NET.

PHP: Please follow the PHP setup instructions on the client libraries page and then visit the Natural Language reference documentation for PHP.

Ruby: Please follow the Ruby setup instructions on the client libraries page and then visit the Natural Language reference documentation for Ruby.

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