6/29/2023 0 Comments Regex curly bracketsNote: Both pattern1 and pattern2 are required.Do regular expressions secretly terrify you? Don’t worry, you can admit it - fear of regex is not some shameful quirk you need to keep hidden. The "(?!…)… meta-characters say that if the first pattern is not present, pattern1, then accept the second pattern, pattern2.įor example, /(?!x)car/ matches "car" it will not match "xcar". Note: The syntax differences between this match rule and the following three are where the pattern is inside the parentheses. And "(?i)cars?" will match "Car", "Cars", "CarS", and so on. The "(?i)" meta-characters indicate that the following pattern should ignore the case of letters when performing the match.įor example, the pattern "(?i)car" will match "Car", "car", "cAR", and so on. Matches any character other than white space characters. Matches any white space character including a tab or a space. Matches all non-digits including white space. Identical to "".įor example, "/\d /" will match one or more digits. Matches any character that is not alphanumeric and not underscore. Matches any alphanumeric character or the underscore. A "\w" will match a sequence of alphanumeric characters not interrupted by white space, see the following description. The character "w" will normally match "w". In this case a "\*" matches the star character. Matches against characters that normally have special meaning such as star (*) and dot (.), see preceding descriptions. The pipe (|) character matches either "x" or "y", where "x" or "y" are blocks of characters.įor example, "car|bus" will match either "car" or "bus". Note: The parentheses are equivalent to "(?:…)" The parentheses are used to group characters.įor example, "(cars?)|bus" will match "car", "cars", or "bus". When using the dash to define a range of characters, the first character must precede the second character in alphabetic or numeric order.įor example, "" is valid, but "" is not valid. For example, "" matches any lowercase letter, and "" matches any uppercase letter. Within square brackets, a range of characters can be defined using the dash (-). A range of characters in the alphabet can be matched using the hyphen.įor example, "// "will match any of "x", "y", or "z". The square brackets match any one of characters inside the brackets. If m is not present then the pattern is matched n or more times.įor example, "/x/" matches "xx" and "xxx". This form of the curly brackets is used to match the preceding character or pattern from n to m times, with n greater than m. Note: The curly brackets are used in the application to differentiate white space bounded text or characters from text or characters that are embedded among other characters with no identifiable white space. The curly brackets are used to match exactly n instances of the proceeding character or pattern. The question mark character matches the preceding pattern or character zero or once.įor example, "/ca?r/" matches both "car" and "cr" it will not match "caar". The plus sign matches the preceding pattern or character one or more times.įor example, /ca r/ matches the following text fragments: "car", "caar" and "caaar", but will not match "cr". The asterisk matches the preceding pattern or character zero or more times.įor example, "/fo*/" matches the following text fragments:Ĭombining the period and asterisk, "/a.*b/" will match "a5b", "a55b", "a123b", and so on. The dot character matches any single character.įor example, the terminology rule regular expression, "/a.b/", matches all text where there is an "a" followed by any single character, followed by a "b", as in, "a5b".
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