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    Session: How to Use MoreLikeThis

    MoreLikeThis is available through query extension methods and will return similar documents according to the provided criteria and options.

    Syntax

    IRavenQueryable<T> MoreLikeThis<T>(MoreLikeThisBase moreLikeThis);

IRavenQueryable<T> MoreLikeThis<T>(Action<IMoreLikeThisBuilder<T>> builder);
    Parameters
    moreLikeThis MoreLikeThisBase Defines the type of MoreLikeThis that should be executed
    builder Action<IMoreLikeThisFactory<T>> Builder with fluent API that constructs the MoreLikeThisBase instance

    Builder

    IMoreLikeThisOperations<T> UsingAnyDocument();

IMoreLikeThisOperations<T> UsingDocument(string documentJson);

IMoreLikeThisOperations<T> UsingDocument(Expression<Func<T, bool>> predicate);

IMoreLikeThisOperations<T> WithOptions(MoreLikeThisOptions options);
    Parameters
    documentJson string Inline JSON document that will be used as a base for operation
    predicate Expression<Func<T, bool>> Filtering expression utilized to find a document that will be used as a base for operation
    options MoreLikeThisOptions Non-default options that should be used for operation

    Options

    public int? MinimumTermFrequency { get; set; } = 2;

public int? MaximumQueryTerms { get; set; } = 25;

public int? MaximumNumberOfTokensParsed { get; set; } = 5000;

public int? MinimumWordLength { get; set; } = 0;

public int? MaximumWordLength { get; set; } = 0;

public int? MinimumDocumentFrequency { get; set; } = 5;

public int? MaximumDocumentFrequency { get; set; } = int.MaxValue;

public int? MaximumDocumentFrequencyPercentage { get; set; }

public bool? Boost { get; set; } = false;

public float? BoostFactor { get; set; } = 1;

public string StopWordsDocumentId { get; set; }

public string[] Fields { get; set; }
    Options
    MinimumTermFrequency int? Ignores terms with less than this frequency in the source doc
    MaximumQueryTerms int? Returns a query with no more than this many terms
    MaximumNumberOfTokensParsed int? The maximum number of tokens to parse in each example doc field that is not stored with TermVector support
    MinimumWordLength int? Ignores words less than this length or, if 0, then this has no effect
    MaximumWordLength int? Ignores words greater than this length or if 0 then this has no effect
    MinimumDocumentFrequency int? Ignores words which do not occur in at least this many documents
    MaximumDocumentFrequency int? Ignores words which occur in more than this many documents
    MaximumDocumentFrequencyPercentage int? Ignores words which occur in more than this percentage of documents
    Boost bool? Boost terms in query based on score
    BoostFactor float? Boost factor when boosting based on score
    StopWordsDocumentId string Document ID containing custom stop words
    Fields string[] Fields to compare

    Example I

    // Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
List<Article> articles = session
    .Query<Article>("Articles/MoreLikeThis")
    .MoreLikeThis(builder => builder
        .UsingDocument(x => x.Id == "articles/1")
        .WithOptions(new MoreLikeThisOptions
        {
            Fields = new[] { "Body" }
        }))
    .ToList();
    // Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
List<Article> articles = await asyncSession
    .Query<Article>("Articles/MoreLikeThis")
    .MoreLikeThis(builder => builder
        .UsingDocument(x => x.Id == "articles/1")
        .WithOptions(new MoreLikeThisOptions
        {
            Fields = new[] { "Body" }
        }))
    .ToListAsync();
    from index 'Articles/MoreLikeThis' 
where morelikethis(id() = 'articles/1', '{ "Fields" : [ "Body" ] }')

    Example II

    // Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
// where article category is 'IT'
List<Article> articles = session
    .Query<Article>("Articles/MoreLikeThis")
    .MoreLikeThis(builder => builder
        .UsingDocument(x => x.Id == "articles/1")
        .WithOptions(new MoreLikeThisOptions
        {
            Fields = new[] { "Body" }
        }))
    .Where(x => x.Category == "IT")
    .ToList();
    // Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'Body'
// where article category is 'IT'
List<Article> articles = await asyncSession
    .Query<Article>("Articles/MoreLikeThis")
    .MoreLikeThis(builder => builder
        .UsingDocument(x => x.Id == "articles/1")
        .WithOptions(new MoreLikeThisOptions
        {
            Fields = new[] { "Body" }
        }))
    .Where(x => x.Category == "IT")
    .ToListAsync();
    from index 'Articles/MoreLikeThis' 
where morelikethis(id() = 'articles/1', '{ "Fields" : [ "Body" ] }') and Category == 'IT'

    Remarks

    Do not forget to add the following using statement which contains necessary extensions:

    using Raven.Client.Documents;

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