\t\t\t\tUnderstanding the sentiment of an email or text message can be difficult. Someone may send a message, intending for it to be encouraging, but it may be accidentally interpreted as mean or condescending.<\/p>\n
Luckily, Microsoft’s Text Analytics Service<\/a> can help avoid any confusion.<\/p>\n Microsoft’s Cognitive Services<\/a> team have created the Sentiment Analysis API<\/a> that uses machine learning to determine the text sentiment. And the best part is, you don’t need to be machine learning experts to use it.<\/p>\n You just submit the text in a POST Request, specifying the text’s language and a GUID Id.<\/p>\n Then the API returns back its sentiment score:<\/p>\n The sentiment score ranges between 0 and 1.<\/p>\n Scores close to 0 indicate negative sentiment, while scores close to 1 indicate positive sentiment.<\/p>\n Now let’s add it to a Xamarin app.<\/p>\n Let’s upgrade a Xamarin app to include text sentiment analysis.<\/p>\n The completed Xamarin.Forms app can be found here: https:\/\/github.com\/brminnick\/SentimentAnalysis<\/a>.<\/p>\n First, you’ll need to generate a Text Analytics API Key using the Azure Portal<\/p>\n Next, let’s add the following NuGet Packages to our Xamarin app. Make sure to install these in each C# Project, including the .NET Standard project, the iOS-specific project, and Android-specific project:<\/p>\n – Microsoft.Azure.CognitiveServices.Language.TextAnalytics v2.1.0-preview<\/a>\n– Newtonsoft.Json v11.0.2<\/a><\/p>\n The TextAnalytics\u00a0SDK is a library that contains all of the boiler-plate code necessary for accessing the TextAnalytics API, including the C# Models and the HttpClient logic. You aren’t required to use the SDK, but it certainly saves you from writing many lines of code.<\/p>\n Now let’s implement the Sentiment Service in our Xamarin app.<\/p>\n This code leverages the TextAnalytics SDK’s helper classes which call the Sentiment API. This allows us to implement a Sentiment Service with just a few lines of code.<\/p>\n Make sure to add your API KEY and your Base Url from your Azure Text Analytics resource.<\/p>\n using<\/span> System<\/span>;<\/span>\nusing<\/span> System.Collections.Generic<\/span>;<\/span>\nusing<\/span> System.Linq<\/span>;<\/span>\nusing<\/span> System.Net.Http<\/span>;<\/span>\nusing<\/span> System.Threading<\/span>;<\/span>\nusing<\/span> System.Threading.Tasks<\/span>;<\/span>\nusing<\/span> Microsoft.Azure.CognitiveServices.Language.TextAnalytics<\/span>;<\/span>\nusing<\/span> Microsoft.Azure.CognitiveServices.Language.TextAnalytics.Models<\/span>;<\/span>\nusing<\/span> Microsoft.Rest<\/span>;<\/span><\/p>\n namespace<\/span> SentimentAnalysis\n{<\/span>\n\u00a0 \u00a0 public<\/span> static<\/span> class<\/span> SentimentService\n\u00a0 \u00a0 <\/span>{<\/span>\n\u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\/\/Example Base Url: https:\/\/westus.api.cognitive.microsoft.com<\/span>\n\u00a0 \u00a0 \u00a0 \u00a0 <\/span>const<\/span> string<\/span> _sentimentAPIBaseUrl =<\/span> “Add Your API’s Base Url Here”<\/span>;<\/span>\n\u00a0 \u00a0 \u00a0 \u00a0 <\/span>const<\/span> string<\/span> _textSentimentAPIKey =<\/span> “Add Your API Key Here”<\/span>;<\/span><\/p>\n \u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\/\/HttpClient wrapper for accessing the TextAnalytics API<\/span>\n\u00a0 \u00a0 \u00a0 \u00a0 <\/span>readonly<\/span> static<\/span> TextAnalyticsClient _textAnalyticsApiClient =<\/span> new<\/span><\/a> TextAnalyticsClient(<\/span>new\u00a0<\/span><\/a>ApiKeyServiceClientCredentials(<\/span>_textSentimentAPIKey)<\/span>)<\/span>\n\u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span><\/span>{<\/span>\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <\/span><\/span>Endpoint =<\/span> _sentimentAPIBaseUrl\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>}<\/span>;<\/span><\/p>\n \u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\/\/Input the text to be analyzed and return its sentiment score. The sentiment score will range from 0 to 1, where 0 is negative sentiment and 1 is positive sentiment.<\/span>\n\u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>public<\/span> static<\/span> async Task<<\/span>double<\/span>?><\/span> GetSentiment(<\/span>string<\/span> text)<\/span>\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>{<\/span>\n\u00a0 \u00a0 \u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\/\/Create the request object to send to the TextAnalytics API<\/span>\n\u00a0 \u00a0\u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\/\/The request can contain multiple text inputs which you can use to batch multiple requests into one API call<\/span>\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>var request =<\/span> new<\/span><\/a> MultiLanguageBatchInput(<\/span>new<\/span><\/a> List<<\/span>MultiLanguageInput><\/span>\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>{<\/span>\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 \u00a0 \u00a0 <\/span><\/span>{<\/span> new<\/span><\/a> MultiLanguageInput(<\/span>id:<\/span> “1”<\/span>, text:<\/span> text)<\/span> }<\/span>\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>}<\/span>)<\/span>;<\/span><\/p>\n \u00a0 \u00a0 <\/span>\u00a0 \u00a0 \u00a0 \u00a0 <\/span>\/\/Get the sentiment results from the TextAnalytics API <\/span>\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>var sentimentResult =<\/span> await _textAnalyticsApiClient.<\/span>SentimentAsync<\/span>(<\/span>request)<\/span>;<\/span><\/p>\n \u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\/\/Parse the sentiment score <\/span>\n\u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>return<\/span> sentimentResult?.<\/span>Documents<\/span>?.<\/span>FirstOrDefault<\/span>(<\/span>)<\/span>?.<\/span>Score<\/span>;<\/span>\n\u00a0 \u00a0 <\/span><\/span>\u00a0 \u00a0 <\/span><\/span>}<\/span><\/p>\n \u00a0 \u00a0 <\/span>\u00a0 \u00a0 <\/span>\/\/Helper class to add our API Key to the HttpRequestMessage Header<\/span>\n\u00a0 \u00a0 <\/span><\/span>Text Analytics Service<\/h2>\n
{\r\n \"documents\": [\r\n {\r\n \"language\": \"en\",\r\n \"id\": \"251c99d7-1f89-426a-a3ad-c6fa1b34f020\",\r\n \"text\": \"I hope you find time to actually get your reports done today.\"\r\n }\r\n ]\r\n}<\/pre>\n{\r\n\"sentiment\": {\r\n \"documents\": [\r\n {\r\n \"id\": \"251c99d7-1f89-426a-a3ad-c6fa1b34f020\",\r\n \"score\": 0.776355504989624\r\n }\r\n ]\r\n}<\/pre>\nSentiment Analysis + Xamarin<\/h2>\n
1. Generate Text Analytics API Key<\/h3>\n
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2. Install NuGet Packages<\/h3>\n
3. Implement the Sentiment Service<\/h3>\n