Remove elements/objects From Array in ElasticSearch Followed by Matching Query

Question

I have below types documents.

{
"_index": "example1",
"_type": "doc",
"_id": "8036",
"_score": 1,
"_source": {
  "user": "kimchy8036",
  "postDate": "2009-11-15T13:12:00",
  "locations": [
    [
      72.79887719999999,
      21.193036000000003
    ],
    [
      -1.8262150000000001,
      51.178881999999994
    ]
  ]
  }
} 

And below is mapping:

   {
        "example1": {
        "mappings": {
        "doc": {
        "properties": {
        "locations": {
        "type": "geo_point"
        },
        "postDate": {
        "type": "date"
        },
        "status": {
        "type": "long"
        },
        "user": {
        "type": "text",
        "fields": {
        "keyword": {
        "type": "keyword",
        "ignore_above": 256
        }
        }
        }
        }
        }
        }
        }
            }

I can add multiple locations using below query.

POST /example1/_update_by_query
    {
    "query": {
    "match": {
    "_id": "3"
    }
    },
    "script" : {
    "lang":"painless",
    "inline": "ctx._source.locations.add(params.newsupp)",
    "params":{
    "newsupp":[-74.00,41.12121 ]
    }}
    }

But not able remove array objects from locations. I have tried below query but working. POST example1/doc/3/_update {

    "script" :
    {
    "lang":"painless",
    "inline":"ctx._source.locations.remove(params.tag)",
    "params":{
    "tag":[-74.00,41.12121]
    }
    }
    }

Kindly let me know where i am doing wrong here. I am using elastic version 5.5.2

Answer 1

Unlike add() , remove() takes the index of the element and remove it.

Your ctx._source.locations in painless is an ArrayList . It has List 's remove() method:

E remove(int index)

Removes the element at the specified position in this list (optional operation). ...

See Painless API - List for other methods.

See this answer for example code.

Answer 2

In painless scripts, Array.remove() method removes by index, not by value.

Here's a working example that removes array elements by value in Elasticsearch script:

POST objects/_update_by_query
{
    "query": {
        ...  // use regular ES query to remove only in relevant documents
    },
    "script": {
        "source": """
            if (ctx._source[params.array_attribute] != null) {
                for (int i=ctx._source[params.array_attribute].length-1; i>=0; i--) {
                    if (ctx._source[params.array_attribute][i] == params.value_to_remove) {
                        ctx._source[params.array_attribute].remove(i);
                    }
                }
            }
        """,
        "params": {
            "array_attribute": "<NAME_OF_ARRAY_PROPERTY_TO_REMOVE_VALUE_IN>",
            "value_to_remove": "<VALUE_TO_REMOVE_FROM_ARRAY>",
        }
    }
}

You might want to simplify script, if your script shall only remove values from one specific array attribute. For example, removing "green" from document's .color_list array:

_doc/001 = {
    "color_list": ["red", "blue", "green"]
}

Script to remove "green" :

POST objects/_update_by_query
{
    "query": {
        ...  // use regular ES query to remove only in relevant documents
    },
    "script": {
        "source": """
            for (int i=ctx._source.color_list.length-1; i>=0; i--) {
                if (ctx._source.color_list[i] == params.color_to_remove) {
                    ctx._source.color_list.remove(i);
                }
            }
        """,
        "params": {
            "color_to_remove": "green"
        }
    }
}

Answer 3

"script" : {
    "lang":"painless",
    "inline":"ctx._source.locations.remove(params.tag)",
    "params":{
      "tag":indexToRemove
    }
}

If with ctx._source.locations.add(elt) You add the element, with ctx._source.locations.remove(indexToRemove) , you remove by the index of element in the array.