How to write a simple regexp query using elasticsearch in python?

Question

I am trying to write a simple regexp query using elasticsearch in python that just won't work. Can anybody tell me where I'm going wrong ?

result = es.search(index="my-index", body={"query": {"regexp": {"Name": "Vi.*" }}})

The indexed document is a list of names with my name also in it (Vitthal Bhandari). The above query always yields empty results when it should return my name instead. The document is properly indexed and other queries work just fine. For instance a match query gives the required result.

result = es.search(index="my-index", body={"query": {"match": {"Name": "Vitthal" }}})

What is the problem with the regexp query that I'm writing that it won't give any result? Any suggestions?

**EDIT : ** The "Name" mapping is given below :

"Name" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },

Add a sample document and mapping of name also – Gibbs Jun 23 '20 at 08:54 — Gibbs, Jun 23 '20 at 08:54

score 3 · Accepted Answer · answered Jun 23 '20 at 09:45

3

As per your mapping

"Name" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        }

You have default analyzer

To make it work:

{"query": {"regexp": {"Name": "vi.*" }}}

Use lower case.

Reason for Vi.* not working:

regexp is a term query. It is not a full text search query.

Unlike full-text queries, term-level queries do not analyze search terms. Instead, term-level queries match the exact terms stored in a field.

So, it expects terms starting with Vi in the index which is not true as it is analysed and stored as vi..

Reference

answered Jun 23 '20 at 09:45

Gibbs

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Thanks for the solution. It worked. While we're at it can you help me with another thing. The next step in my program is to get the search string as an input from the user, i.e., in above example the string "Vi" is to be taken as input from user at run time. Let's say the string is stored in a variable str. How do I formulate a query using str ? – VITTHAL BHANDARI Jun 23 '20 at 10:08
Please reply to my comment at [here](https://stackoverflow.com/questions/62530521/python-wildcard-query-in-elasticsearch) – Gibbs Jun 23 '20 at 10:14

score 1 · Answer 2 · answered Jun 23 '20 at 09:04

1

Use

{
  "query": {
    "regexp": {
      "Name": "vi.*"
    }
  }
}

or

{
  "query": {
    "regexp": {
      "Name.keyword": "Vi.*"
    }
  }
}

answered Jun 23 '20 at 09:04

Joe - GMapsBook.com

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How to write a simple regexp query using elasticsearch in python?

2 Answers2