Filter by RegEx
Description
Selects objects by the value of a string property, using regular expression replacement.
Input
SOURCE [OBJ]
: the list of objects to filter
Output
TRUE [OBJ]
: the objects for which the selection appliesFALSE [OBJ]
: the objects for which the selection does not apply
Parameters
Property
: the string property to check. Use*
to consider all properties.Use sub-properties
: when set totrue
, the values of all sub-properties are also included. Sub-properties can be defined in the data with therdfs:subPropertyOf
relation.Pattern RegEx
: the regular expression to use for the match.Language
: when a language is selected, only the strings in this language are extracted. This uses the language tags that are defined in the data.Case-sensitive
: if set tofalse
, upper/lower case is ignored
Output scores can be aggregated and/or normalized.
Regular Expressions
Regular expressions are internally evaluated by a PCRE engine. For a syntax reference, see this page. For a 1-page syntax reference, see this cheat-sheet.
Some of the Most Common Questions and Mistakes
- Regular expressions are different from glob patterns using wildcards.
In particular,
*
does NOT mean "anything",.*
does. - All special characters (
. * + ? | \ ( ) [ ] ^ $
) must be escaped (prefixed with\
) when they are meant literally, in thePattern RegEx
. ^
indicates the beginning of an input text, or negation when used inside a multiple choice (e.g.,[^\d-_]
).$
indicates the end of an input text.\b
indicates a word-boundary (spaces, punctuation, etc.).
Examples
- Find names in the form of
Smith, John
:Pattern RegEx
:\b[^,]+\s*,\s*\b\w+\b
- Find any day of the week (with
Case-sensitive = false
):Pattern RegEx
:\b(mon|tue|wednes|thurs|fri|sat|sun)day\b