# normalizer(歸一化) **[`keyword`](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/keyword.html "Keyword datatype")****?fields**（關鍵字字段）?的?**`normalizer`**`（`歸一化）屬性與?[`analyzer`](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/analyzer.html "analyzer")`（`分析器）類似,只不過它保證?**analysis chain**（分析鏈）生成單一的?**`token?`**`（詞元`）. **`normalizer`**`（`歸一化）應用于索引?**keyword**（關鍵字）**?**之前,以及諸如在?**`[match](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-match-query.html)?query?`**(匹配查詢),查詢解析器搜索?**keyword****?fields**（關鍵字字段）的時候. | `curl -XPUT?``'localhost:9200/index?pretty'`?`-H?``'Content-Type: application/json'`?`-d``'` `{` `"settings": {` `"analysis": {` `"normalizer": {` `"my_normalizer": {` `"type": "custom",` `"char_filter": [],` `"filter": ["lowercase", "asciifolding"]` `}` `}` `}` `},` `"mappings": {` `"type": {` `"properties": {` `"foo": {` `"type": "keyword",` `"normalizer": "my_normalizer"` `}` `}` `}` `}` `}` `'` `curl -XPUT?``'localhost:9200/index/type/1?pretty'`?`-H?``'Content-Type: application/json'`?`-d``'` `{` `"foo": "BàR"` `}` `'` `curl -XPUT?``'localhost:9200/index/type/2?pretty'`?`-H?``'Content-Type: application/json'`?`-d``'` `{` `"foo": "bar"` `}` `'` `curl -XPUT?``'localhost:9200/index/type/3?pretty'`?`-H?``'Content-Type: application/json'`?`-d``'` `{` `"foo": "baz"` `}` `'` `curl -XPOST?``'localhost:9200/index/_refresh?pretty'` `curl -XGET?``'localhost:9200/index/_search?pretty'`?`-H?``'Content-Type: application/json'`?`-d``'` `{` `"query": {` `"match": {` `"foo": "BAR"` `}` `}` `}` `'` | 上述查詢與?**documents（文檔）?1**?和?**2**?相匹配,這是因為在索引和查詢的時候都將?**`BAR?`**轉換為了?**`bar`**. | `{` `"took"``: $body.took,` `"timed_out"``:?``false``,` `"_shards"``: {` `"total"``: 5,` `"successful"``: 5,` `"failed"``: 0` `},` `"hits"``: {` `"total"``: 2,` `"max_score"``: 0.2876821,` `"hits"``: [` `{` `"_index"``:?``"index"``,` `"_type"``:?``"type"``,` `"_id"``:?``"2"``,` `"_score"``: 0.2876821,` `"_source"``: {` `"foo"``:?``"bar"` `}` `},` `{` `"_index"``:?``"index"``,` `"_type"``:?``"type"``,` `"_id"``:?``"1"``,` `"_score"``: 0.2876821,` `"_source"``: {` `"foo"``:?``"BàR"` `}` `}` `]` `}` `}` | 此外,**keywords?**在索引之前轉換意味著聚合返回?**normalised?values**（歸一化的值）: | `curl -XGET?``'localhost:9200/index/_search?pretty'`?`-H?``'Content-Type: application/json'`?`-d``'` `{` `"size": 0,` `"aggs": {` `"foo_terms": {` `"terms": {` `"field": "foo"` `}` `}` `}` `}` `'` | 返回 | `{` `"took"``: 43,` `"timed_out"``:?``false``,` `"_shards"``: {` `"total"``: 5,` `"successful"``: 5,` `"failed"``: 0` `},` `"hits"``: {` `"total"``: 3,` `"max_score"``: 0.0,` `"hits"``: []` `},` `"aggregations"``: {` `"foo_terms"``: {` `"doc_count_error_upper_bound"``: 0,` `"sum_other_doc_count"``: 0,` `"buckets"``: [` `{` `"key"``:?``"bar"``,` `"doc_count"``: 2` `},` `{` `"key"``:?``"baz"``,` `"doc_count"``: 1` `}` `]` `}` `}` `}` |