# REGEXMATCH

The `REGEXMATCH` field specifier matches documents where a specified field value (the entire value, not just part of it) matches a regular expression. The regular expression matches field values case-insensitively.

NOTE: This field specifier is optimized for `MatchType` fields, and `ParametricType` fields when `ParametricNumericMapping` is `TRUE`.

## Format

    FieldText=REGEXMATCH{regex}:fields

`regex` | A regular expression. A document is returned only if the entire field value matches the regular expression.
`fields` | A colon-separated list of field names (there must be no space before or after a colon). A document is returned only if the value in at least one of the fields matches your regular expression.

## Examples

In the following example, the `COUNTRY` field must match either "United Kingdom" or "United States".

`FieldText=REGEXMATCH{United (Kingdom|States)}:COUNTRY`

The query would not match a document if the `COUNTRY` field contained the value "The United Kingdom", because the entire value must match the regular expression.

In the following example, the `PAGECOUNT` or `TOTALPAGES` field must contain either two or three digits.

`FieldText=REGEXMATCH{\d\d\d?}:PAGECOUNT:TOTALPAGES`

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