Classify text

Analyze text and return a list of content categories that apply to the text.

Explore further

For detailed documentation that includes this code sample, see the following:

Code sample

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 classifyText(ctx context.Context, client *language.Client, text string) (*languagepb.ClassifyTextResponse, error) {
	return client.ClassifyText(ctx, &languagepb.ClassifyTextRequest{
		Document: &languagepb.Document{
			Source: &languagepb.Document_Content{
				Content: text,
			},
			Type: languagepb.Document_PLAIN_TEXT,
		},
		ClassificationModelOptions: &languagepb.ClassificationModelOptions{
			ModelType: &languagepb.ClassificationModelOptions_V2Model_{
				V2Model: &languagepb.ClassificationModelOptions_V2Model{
					ContentCategoriesVersion: languagepb.ClassificationModelOptions_V2Model_V2,
				},
			},
		},
	})
}

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()) {
  // Set content to the text string
  Document doc = Document.newBuilder().setContent(text).setType(Type.PLAIN_TEXT).build();
  ClassifyTextRequest request = ClassifyTextRequest.newBuilder().setDocument(doc).build();
  // Detect categories in the given text
  ClassifyTextResponse response = language.classifyText(request);

  for (ClassificationCategory category : response.getCategoriesList()) {
    System.out.printf(
        "Category name : %s, Confidence : %.3f\n",
        category.getName(), category.getConfidence());
  }
}

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');

// Creates a client
const client = new language.LanguageServiceClient();

/**
 * TODO(developer): Uncomment the following line to run this code.
 */
// const text = 'Your text to analyze, e.g. Hello, world!';

// Prepares a document, representing the provided text
const document = {
  content: text,
  type: 'PLAIN_TEXT',
};

const classificationModelOptions = {
  v2Model: {
    contentCategoriesVersion: 'V2',
  },
};

// Classifies text in the document
const [classification] = await client.classifyText({
  document,
  classificationModelOptions,
});
console.log('Categories:');
classification.categories.forEach(category => {
  console.log(`Name: ${category.name}, Confidence: ${category.confidence}`);
});

PHP

To learn how to install and use the client library for Natural Language, see Natural Language client libraries.

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

use Google\Cloud\Language\V1\ClassifyTextRequest;
use Google\Cloud\Language\V1\Client\LanguageServiceClient;
use Google\Cloud\Language\V1\Document;
use Google\Cloud\Language\V1\Document\Type;

/**
 * @param string $text The text to analyze
 */
function classify_text(string $text): void
{
    // Make sure we have enough words (20+) to call classifyText
    if (str_word_count($text) < 20) {
        printf('20+ words are required to classify text.' . PHP_EOL);
        return;
    }
    $languageServiceClient = new LanguageServiceClient();

    // Create a new Document, add text as content and set type to PLAIN_TEXT
    $document = (new Document())
        ->setContent($text)
        ->setType(Type::PLAIN_TEXT);

    // Call the analyzeSentiment function
    $request = (new ClassifyTextRequest())
        ->setDocument($document);
    $response = $languageServiceClient->classifyText($request);
    $categories = $response->getCategories();
    // Print document information
    foreach ($categories as $category) {
        printf('Category Name: %s' . PHP_EOL, $category->getName());
        printf('Confidence: %s' . PHP_EOL, $category->getConfidence());
        print(PHP_EOL);
    }
}

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_v1


def sample_classify_text(text_content):
    """
    Classifying Content in a String

    Args:
      text_content The text content to analyze.
    """

    client = language_v1.LanguageServiceClient()

    # text_content = "That actor on TV makes movies in Hollywood and also stars in a variety of popular new TV shows."

    # Available types: PLAIN_TEXT, HTML
    type_ = language_v1.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 = "en"
    document = {"content": text_content, "type_": type_, "language": language}

    content_categories_version = (
        language_v1.ClassificationModelOptions.V2Model.ContentCategoriesVersion.V2
    )
    response = client.classify_text(
        request={
            "document": document,
            "classification_model_options": {
                "v2_model": {"content_categories_version": content_categories_version}
            },
        }
    )
    # Loop through classified categories returned from the API
    for category in response.categories:
        # Get the name of the category representing the document.
        # See the predefined taxonomy of categories:
        # https://cloud.google.com/natural-language/docs/categories
        print(f"Category name: {category.name}")
        # Get the confidence. Number representing how certain the classifier
        # is that this category represents the provided text.
        print(f"Confidence: {category.confidence}")

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