Standard Analyzer

The standard analyzer is the default for all Atlas Search indexes and queries. It divides text into terms based on word boundaries, which makes it language-neutral for most use cases. It converts all terms to lower case and removes punctuation. It provides grammar-based tokenization that recognizes email addresses, acronyms, Chinese-Japanese-Korean characters, alphanumerics, and more.

If you select Refine Your Index, the Atlas UI displays a section titled View text analysis of your selected index configuration within the Index Configurations section. If you expand this section, the Atlas UI displays the index and search tokens that the standard analyzer generates for each sample string. You can see the tokens that the standard analyzer creates for a built-in sample document and query string when you create or edit an index in the Atlas UI Visual Editor.

Important

Atlas Search won't index string fields where analyzer tokens exceed 32766 bytes in size. If using the keyword analyzer, string fields which exceed 32766 bytes will not be indexed.

Example

The following example index definition specifies an index on the title field in the sample_mflix.movies collection using the standard analyzer. To follow along with this example, load the sample data on your cluster and either use mongosh or navigate to the Create a Search Index page in the Atlas UI following the steps in the Create an Atlas Search Index tutorial.

Then, using the movies collection as your data source, follow the example procedure to create an index from mongosh or the Atlas UI Visual Editor or JSON editor.

➤ Use the Select your language drop-down menu to set the interface for the example on this page.

Click Refine Your Index to configure your index.
In the Index Configurations section, toggle Dynamic Mapping to off.
In the Field Mappings section, click Add Field Mapping to open the Add Field Mapping window.
Click Customized Configuration.
Select title from the Field Name dropdown.
Click the Data Type dropdown and select String if it isn't already selected.

Expand String Properties and make the following changes:

Index Analyzer	Select `lucene.standard` from the dropdown if it isn't already selected.
Search Analyzer	Select `lucene.standard` from the dropdown if it isn't already selected.
Index Options	Use the default `offsets`.
Store	Use the default `true`.
Ignore Above	Keep the default setting.
Norms	Use the default `include`.

Click Add.
Click Save Changes.
Click Create Search Index.

Replace the default index definition with the following index definition.

{
  "mappings": {
    "fields": {
      "title": {
        "type": "string",
        "analyzer": "lucene.standard"
      }
    }
  }
}

Click Next.
Click Create Search Index.

1 db.movies.createSearchIndex(
2   "default",
3     {
4       "mappings": {
5         "fields": {
6           "title": {
7             "type": "string",
8             "analyzer": "lucene.standard"
9           }
10         }
11       }
12     }
13 )

The following query searches the title field for the term action and limits the output to two results.

Click the Query button for your index.
Click Edit Query to edit the query.
Click on the query bar and select the database and collection.

Replace the default query with the following and click Find:

[
  {
    "$search": {
      "text": {
        "query": "action",
        "path": "title"
      }
    }
  }
]

SCORE: 4.001246452331543  _id: "573a1398f29313caabceac7f"
  awards: Object
  cast: Array (4)
  countries: Array (1)
  directors: Array (1)
  fullplot: "Jericho "Action" Jackson is a Detroit police sergeant who was demoted …"
  genres: Array (3)
  imdb: Object
  languages: Array (1)
  lastupdated: "2015-08-20 00:24:08.470000000"
  num_mflix_comments: 2
  plot: "Vengence drives a tough Detroit cop to stay on the trail of a power hu…"
  poster: "https://m.media-amazon.com/images/M/MV5BZWFhNmI3OWQtOTU5Zi00ODA3LWExNj…"
  rated: "R"
  released: 1988-02-12T00:00:00.000+00:00
  runtime: 96
  title: "Action Jackson"
  tomatoes: Object
  type: "movie"
  writers: Array (1)
  year: 1988
 SCORE: 4.001246452331543  _id:  "573a1399f29313caabcec6b7"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Jeb Ward is an attorney who specializes in whistle blower, David vs. Goliath cases. When a major auto manufacturer is accused of knowingly marketing a defective car, Ward takes on the case, risking everything."
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-06 00:42:51.167000000"
   metacritic: 58
   num_mflix_comments: 2
   plot: "Jeb Ward is an attorney who specializes in whistle blower, David vs. Goliath cases."
   poster: "https://m.media-amazon.com/images/M/MV5BNWY5Mjk4ZmItMTAzYS00NWE3LWEzYz…"
   rated: "R"
   released: 1991-03-15T00:00:00.000+00:00
   runtime: 110
   title: "Class Action"
   tomatoes: Object
   type: "movie"
   writers: Array (3)
   year: 1991
 SCORE: 4.001246452331543  _id:  "573a13b0f29313caabd333e7"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (1)
   fullplot: "Vishi is a local goon who basically likes beating up people to get his way. He falls in love with Khushi, but his life takes a turn when he crosses paths with a ruthless mafia kingpin."
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-10 17:20:55.697000000"
   num_mflix_comments: 1
   plot: "In order to escape crime and clutches of a ruthless mafia, a Bangkok based goon seeks help from his lookalike, a Mumbai based criminal."
   released: 2014-12-05T00:00:00.000+00:00
   runtime: 144
   title: "Action Jackson"
   tomatoes: Object
   type: "movie"
   writers: Array (3)
   year: 2014
 SCORE: 4.001246452331543  _id:  "573a13d2f29313caabd913dc"
   awards: Object
   countries: Array (1)
   directors: Array (1)
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-06-15 03:15:33.967000000"
   num_mflix_comments: 0
   released: 2011-01-28T00:00:00.000+00:00
   runtime: 45
   title: "Slow Action"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2011
 SCORE: 3.440462112426758  _id:  "573a1399f29313caabcedcb0"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Young Danny Madigan is a big fan of Jack Slater, a larger-than-life action hero. When Danny is given a magic ticket, he is transported into Slater's latest adventure."
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-31 00:11:25.920000000"
   metacritic: 44
   num_mflix_comments: 0
   plot: "With the help of a magic ticket, a young film fan is transported into the fictional world of his favorite action movie character."
   poster: "https://m.media-amazon.com/images/M/MV5BNjdhOGY1OTktYWJkZC00OGY5LWJhY2…"
   rated: "PG-13"
   released: 1993-06-18T00:00:00.000+00:00
   runtime: 130
   title: "Last Action Hero"
   tomatoes: Object
   type: "movie"
   writers: Array (4)
   year: 1993
 SCORE: 3.440462112426758  _id:  "573a139af29313caabcf0e84"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Jan Schlichtmann, a tenacious lawyer, is addressed by a group of families whose children have died from leukemia. He takes on a case against two large companies accused of dumping toxic waste."
   genres: Array (1)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-09-07 00:21:34.950000000"
   metacritic: 68
   num_mflix_comments: 0
   plot: "The families of children who died sue two companies for dumping toxic waste."
   poster: "https://m.media-amazon.com/images/M/MV5BZmEzNjhiZWEtNTM5OS00ZmQyLThhYj…"
   rated: "PG-13"
   released: 1999-01-08T00:00:00.000+00:00
   runtime: 115
   title: "A Civil Action"
   tomatoes: Object
   type: "movie"
   writers: Array (2)
   year: 1998
 SCORE: 2.687220573425293  _id:  "573a1398f29313caabcead32"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Colonel James Braddock has a Vietnamese wife who was supposed to leave Vietnam with him, but was left behind. Years later, he returns to rescue her and their son."
   genres: Array (2)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-17 00:28:26.627000000"
   num_mflix_comments: 0
   plot: "Colonel James Braddock has a Vietnamese wife who was supposed to leave Vietnam with him, but was left behind."
   poster: "https://m.media-amazon.com/images/M/MV5BZTRjODU0MTUtMjBmMi00ZTBmLTk2MD…"
   rated: "R"
   released: 1988-03-02T00:00:00.000+00:00
   runtime: 101
   title: "Braddock: Missing in Action III"
   tomatoes: Object
   type: "movie"
   writers: Array (5)
   year: 1988
 SCORE: 2.687220573425293  _id:  "573a13a9f29313caabd1f502"
   awards: Object
   cast: Array (4)
   countries: Array (2)
   directors: Array (1)
   fullplot: "Bugs Bunny and Daffy Duck are up to their feuding ways again. Tired of all the attention going to Bugs, Daffy persuades the studio to let him go off on his own."
   genres: Array (3)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-28 00:30:31.080000000"
   metacritic: 64
   num_mflix_comments: 1
   plot: "The Looney Tunes search for a man's missing father and the mythical Blue Monkey diamond."
   poster: "https://m.media-amazon.com/images/M/MV5BMTkxNDk5MDQ2MF5BMl5BanBnXkFtZT…"
   rated: "PG"
   released: 2003-11-14T00:00:00.000+00:00
   runtime: 91
   title: "Looney Tunes: Back in Action"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2003
 SCORE: 2.4220800399780273  _id:  "573a13bdf29313caabd5acfe"
   awards: Object
   cast: Array (4)
   countries: Array (1)
   directors: Array (1)
   fullplot: "Fueled by the belief that another world is possible, acclaimed filmmaker Velcrow Ripper takes us on a journey through the spiritual activism movement."
   genres: Array (1)
   imdb: Object
   languages: Array (1)
   lastupdated: "2015-08-12 00:50:56"
   num_mflix_comments: 1
   plot: "Captures the exciting movement of Spiritual Activism that is exploding around the planet."
   poster: "https://m.media-amazon.com/images/M/MV5BMTI2MjM2Mzk2NV5BMl5BanBnXkFtZT…"
   released: 2008-10-01T00:00:00.000+00:00
   runtime: 90
   title: "Fierce Light: When Spirit Meets Action"
   tomatoes: Object
   type: "movie"
   writers: Array (1)
   year: 2008

db.movies.aggregate([
  {
    "$search": {
      "text": {
         "query": "action",
         "path": "title"
      }
    }
  },
  {
    "$limit": 2
  },
  {
    "$project": {
      "_id": 0,
      "title": 1
    }
  }
])

[
  {
    title: 'Action Jackson'
  },
  {
    title: 'Class Action'
  }
]

Atlas Search returned these documents because it matched the query term action to the token action for the documents, which Atlas Search created by doing the following for the text in the title field using the lucene.standard analyzer:

Convert the text to lowercase.
Split the text based on word boundaries and create separate tokens.

The following table shows the tokens (searchable terms) that Atlas Search creates using the Standard Analyzer and, by contrast, the tokens that Atlas Search creates for the Keyword Analyzer and Whitespace Analyzer for the documents in the results:

Title	Standard Analyzer Tokens	Keyword Analyzer Tokens	Whitespace Analyzer Tokens
`Action Jackson`	`action`, `jackson`	`Action Jackson`	`Action`, `Jackson`
`Class Action`	`class`, `action`	`Class Action`	`Class`, `Action`

If you index the field using the:

Keyword Analyzer, Atlas Search wouldn't match the documents in the results for the query term action because the keyword analyzer matches only documents in which the search term matches the entire contents of the field (Action Jackson and Class Action) exactly.
Whitespace Analyzer, Atlas Search wouldn't match the documents in the results for the query term action because the whitespace analyzer tokenizes the title field value in its original case (Action) and the query term has the lowercase action, which doesn't match the whitespace analyzer token.

Back

Analyzers

Simple

1	db.movies.createSearchIndex(
2	"default",
3	{
4	"mappings": {
5	"fields": {
6	"title": {
7	"type": "string",
8	"analyzer": "lucene.standard"
9	}
10	}
11	}
12	}
13	)