Is there an NOT operator in Regexes?
Like in that string : "(2001) (asdf) (dasd1123_asd 21.01.2011 zqge)(dzqge) name (20019)"
I want to delete all \([0-9a-zA-z _\.\-:]*\) but not the one where it is a year: (2001).
So what the regex should return must be: (2001) name.
NOTE: something like \((?![\d]){4}[0-9a-zA-z _\.\-:]*\) does not work for me (the (20019) somehow also matches...)
Not quite, although generally you can usually use some workaround on one of the forms
[^abc], which is character by character not a or b or c, a(?!b), which is a not followed by b(?<!a)b, which is b not preceeded by a
[^abc] should mean not a or b or c, not "not the string abc".
%[^sdf] or %(?!(s|d|f)) equals to "contains %", but not "%s", "%d" or "%f".
you(?!tube) or (?<!docker)hub
a(?!b) (a not followed by b) is brillant. Best answer. 👍No, there's no direct not operator. At least not the way you hope for.
You can use a zero-width negative lookahead, however:
\((?!2001)[0-9a-zA-z _\.\-:]*\)
The (?!...) part means "only match if the text following (hence: lookahead) this doesn't (hence: negative) match this. But it doesn't actually consume the characters it matches (hence: zero-width).
There are actually 4 combinations of lookarounds with 2 axes:
\((?![\d]{4})[0-9a-zA-z _\.\-:]+\) there is still (20019) in it
{4} outside the lookahead and in this comment you put it inside: which one did you try? Also: if you want (20019) to match, then you must add the \) inside your lookahead: \((?![\d]{4}\))[0-9a-zA-z _\.\-:]+\)\((?![\d]{4} -->\)<--)[0-9a-zA-z _\.\-:]+\) Then there is a bracket not closed, isn't it?) because I want to match the literal character ) (just as you do at the very beginning and the very end of your regex!). Then after I matched that, I end the lookahead by using an unescaped ).You could capture the (2001) part and replace the rest with nothing.
public static string extractYearString(string input) {
return input.replaceAll(".*\(([0-9]{4})\).*", "$1");
}
var subject = "(2001) (asdf) (dasd1123_asd 21.01.2011 zqge)(dzqge) name (20019)";
var result = extractYearString(subject);
System.out.println(result); // <-- "2001"
.*\(([0-9]{4})\).* means
.* match anything\( match a ( character( begin capture[0-9]{4} any single digit four times) end capture\) match a ) character.* anything (rest of string)Here is an alternative:
(\(\d{4}\))((?:\s*\([0-9a-zA-z _\.\-:]*\))*)([^()]*)(( ?\([0-9a-zA-z _\.\-:]*\))*)
Repetitive patterns are embedded in a single group with this construction, where the inner group is not a capturing one: ((:?pattern)*), which enable to have control on the group numbers of interrest.
Then you get what you want with: \1\3
(2001) name.