# Searching for exactly a hyphenated word

**URL:** <https://discuss.elastic.co/t/searching-for-exactly-a-hyphenated-word/161216>\
**Category:** Elasticsearch\
**Created:** [December 17, 2018, 10:03pm UTC](https://discuss.elastic.co/t/searching-for-exactly-a-hyphenated-word/161216 "2018-12-17T22:03:53Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Daverino](https://avatars.discourse-cdn.com/v4/letter/d/e79b87/32.png) [@Daverino](https://discuss.elastic.co/u/Daverino)\
**Post date:** [December 17, 2018, 10:03pm UTC](https://discuss.elastic.co/t/searching-for-exactly-a-hyphenated-word/161216/1 "2018-12-17T22:03:53Z")

</div>

So this problem has stumped me.

I would like to search for instances of (for example) "hyper-space" but not find "hyper space". All traditional tokenizers except whitespace are going to split on the hyphen and it will be lost to the ether as far as indexing goes. I can use a whitespace tokenizer and then hit it with a word delimiter token filter using the 'preserve original' setting. That will get "hyper-space", "hyper" and "space" all indexed, which is great. Now I can run a term query for "hyper-space" and I get precisely what I need.

But. . .

Since I'm using a whitespace tokenizer and "preserve original" the original may also have trailing punctuation, like "hyper-space,". Now the term query won't match because of that trailing comma. Yuck.

All the possible ways of getting around this start using expensive processors in elasticsearch that I would prefer to avoid. Things like filtering by character or using regexp. Is there a more intuitive solution to this problem that I am missing?

Thanks  
David

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<div class="post-metadata">

**Author:** ![abdon](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/abdon/32/9195_2.png) [@abdon](https://discuss.elastic.co/u/abdon)\
**Post date:** [December 18, 2018, 10:57am UTC](https://discuss.elastic.co/t/searching-for-exactly-a-hyphenated-word/161216/2 "2018-12-18T10:57:31Z")

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You can use an analyzer with a [mapping character filter](https://www.elastic.co/guide/en/elasticsearch/reference/current/analysis-mapping-charfilter.html) that replaces any dashes with a character that is not removed by the tokenizer, for example an underscore.

For example, given this index:

```auto
PUT my_index
{
  "settings": {
    "analysis": {
      "char_filter": {
        "my_char_filter": {
          "type": "mapping",
          "mappings": [
            "- => _"
          ]
        }
      },
      "analyzer": {
        "my_analyzer": {
          "tokenizer": "standard",
          "char_filter": [
            "my_char_filter"
          ],
          "filter": [
            "lowercase"
          ]
        }
      }
    }
  },
  "mappings": {
    "_doc": {
      "properties": {
        "my_field": {
          "type": "text",
          "analyzer": "my_analyzer"
        }
      }
    }
  }
}

```

You can now only find a document containing `hyper-space` if you search for `hyper-space` with a dash:

```auto
# Test the analyzer
GET my_index/_analyze
{
  "text": "foo hyper-space bar",
  "analyzer": "my_analyzer"
}

# Index a document containing "hyper-space"
PUT my_index/_doc/1
{
  "my_field": "foo hyper-space bar"
}

# A query for just "hyper" does not return any hits
GET my_index/_search
{
  "query": {
    "match": {
      "my_field": "hyper"
    }
  }
}

# A query for "hyper space" (without a dash) does not return any hits either
GET my_index/_search
{
  "query": {
    "match": {
      "my_field": "hyper space"
    }
  }
}

# A query for "hyper-space" with a dash does return our document
GET my_index/_search
{
  "query": {
    "match": {
      "my_field": "hyper-space"
    }
  }
}

```

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<div class="post-metadata">

**Author:** ![Daverino](https://avatars.discourse-cdn.com/v4/letter/d/e79b87/32.png) [@Daverino](https://discuss.elastic.co/u/Daverino)\
**Post date:** [December 18, 2018, 3:50pm UTC](https://discuss.elastic.co/t/searching-for-exactly-a-hyphenated-word/161216/3 "2018-12-18T15:50:01Z")

</div>

Thanks! I considered something like this, but I was wondering how expensive a character filter is. I've never included one because it feels like pretty heavy pre-processing.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [January 15, 2019, 3:50pm UTC](https://discuss.elastic.co/t/searching-for-exactly-a-hyphenated-word/161216/4 "2019-01-15T15:50:02Z")

</div>

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