根据单词索引改变搜索顺序

Question

有没有办法给文档开头的术语增加权重？例如，我有3个文档。

Medicine XXX
Sulpher This medicine contains sulpher and should be taken only after consultation with your doctor.

Medicine YYY
contains: sulpher Not recommended by most physicians

Medicine ZZZ
This medicine works like sulpher but does not contain sulpher at all.

对于搜索词 "Sulpher"，文档XXX应该列在最前面，因为那是该文档的第一个词。如果YYY被列在最上面也没关系，因为那和XXX一样。但是ZZZ应该永远是最后一个。换句话说，在 "左边 "找到的术语应该比在文档 "右边 "找到的术语有更高的优先级。

Answer 1

你可以通过小写规范化的术语位置来提升。

PUT sulphur
{
  "settings": {
    "analysis": {
      "normalizer": {
        "keyword_lowercase": {
          "type": "custom",
          "filter": ["lowercase"]
        }
      }
    }
  },
  "mappings": {
    "properties": {
      "text": {
        "type": "text",
        "fields": {
          "keyword": {
            "type": "keyword",
            "normalizer": "keyword_lowercase"
          }
        }
      }
    }
  }
}

POST sulphur/_doc
{"text":"This medicine works like sulpher but does not contain sulpher at all."}
POST sulphur/_doc
{"text":"contains: sulpher Not recommended by most physicians"}
POST sulphur/_doc
{"text":"Sulpher This medicine contains sulpher and should be taken only after consultation with your doctor."}

然后...

GET sulphur/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "function_score": {
            "query": {
              "match": {
                "text": "sulpher"
              }
            },
            "script_score": {
              "script": """
                def pos = doc['text.keyword'].value.indexOf('sulpher');
                return Math.exp((2.0/(pos+1)))
              """
            },
            "boost_mode": "replace"
          }
        }
      ]
    }
  }
}

嫕

[
  {
    "_index":"sulphur",
    "_type":"_doc",
    "_id":"sf5S2nEBW-D5QnrWODvB",
    "_score":7.389056,
    "_source":{
      "text":"Sulpher This medicine contains sulpher and should be taken only after consultation with your doctor."
    }
  },
  {
    "_index":"sulphur",
    "_type":"_doc",
    "_id":"sP5S2nEBW-D5QnrWNjtw",
    "_score":1.1993961,
    "_source":{
      "text":"contains: sulpher Not recommended by most physicians"
    }
  },
  {
    "_index":"sulphur",
    "_type":"_doc",
    "_id":"r_5S2nEBW-D5QnrWNDuw",
    "_score":1.079959,
    "_source":{
      "text":"This medicine works like sulpher but does not contain sulpher at all."
    }
  }
]