The MATCHES operator—available when configuring an attribute filter—supports the use of regular expressions to find a pattern within a target field. Regular expression pattern matching can be a powerful tool for data validation. The full scope and syntax of regular expressions cannot be covered within this topic, but the examples below help illustrate their use in GeoEvent filters.
Regular expressions can only be applied to attribute fields of type string.
The specified pattern is matched against the entire string. You cannot enter California to match strings that contain that substring. Specifying a pattern .*California.* accounts for zero or more characters both before and after the substring the filter is supposed to find.
|Field value||RegEx pattern||Result|
The carat sign (^) anchors the pattern to the beginning of the string, and a dollar sign ($) anchors the pattern to the end of the string. The [0-9]+ portion of the pattern specifies that one or more digits 0 through 9 should be found at the end of the string.
Any values in the target field that do not begin with SWA, followed by some number of digits representing a flight number, will be discarded by the filter.
The use of numeric ranges such as 0 through 1, 0 through 3, and 0 through 9 specifies the expected values for a mm/dd/yy date string. Values that do not have a two-digit month followed by a two-digit day and a four-digit year, separated by a slash (/), will be discarded by the filter.
This pattern verifies that the string in the target field can be interpreted as a numeric value. An asterisk (*) in the RegEx pattern matches zero or more instances of the preceding character; a question mark (?) matches zero or one instances. The backslash means that the '.' is a literal decimal point, not a wildcard (*). The pattern makes a plus (+) or minus (-) sign the integer portion of a floating point value and the literal decimal optional (may occur zero times).