The count API allows to easily execute a query and get the number of matches for that query. It can be executed across one or more indices and across one or more types. The query can either be provided using a simple query string as a parameter, or using the Query DSL defined within the request body.

Fluent DSLedit

var result = client.Count();

The above will do a count query across all indices. (The result type here is not limited)

If you want to limit the scope to a specific index:

var result = client.Count<ElasticsearchProject>();

NEST will infer the index and type, but as usual, you can override the inferrence by specifying the index and type explicitly:

var result = client.Count(c => c
    .Index("elasticsearchprojects")
    .Type("elasticsearchproject")
);

You can also specify multiple indices and types:

var result = client.Count(c => c
    .Indices("elasticsearchprojects", "foo", "bar")
    .Types("elasticsearchproject", "foo", "bar")
);

result is an ICountResponse which contains the document count found in the Count property, along with the shards meta data (total, successful, failed) contained in the Shards property.

Count by Queryedit

Counting the number of documents that match a query is as simple as:

var result = client.Count<ElasticsearchProject>(c => c
    .Query(q => q
        .Match(m => m
            .OnField(p => p.Name)
            .Query("NEST")
        )
    )
);