Bài học theo mô-đun (3/4)
Phủ định: `[^...]`
Placing a caret ^ as the first character inside brackets
inverts the class: it matches any character except those listed.
Pattern: [^aeiou]
Sample: ciao mondo
^ ^^ ^[^aeiou] matches consonants, spaces, punctuation, digits\u2026 everything that
is not a vowel.
Typical examples
[^\s]-- any "non-space" character (equivalent to\S).[^0-9]-- anything that is not a digit (equivalent to\D).[^"]+-- "a sequence of characters that are not double quotes" (useful to extract content between quotes).
Pattern: "([^"]+)"
Sample: Il libro "Il nome della rosa" e' famoso.The group ([^"]+) captures everything between quotes stopping
before the next ": it is a classic trick to avoid the
greedy-vs-lazy problem.
Negation and alternative wildcards
The negated class [^...] consumes exactly one character that is NOT part of the listed set. It is a powerful tool to prevent the engine from running past critical delimiters, avoiding ReDoS caused by infinite backtracking loops.
Try it
Extract the content of every string between double quotes, without capturing the quotes themselves.
Hiển thị gợi ý
Replace .+ with [^"]+: this way the match stops at the next quote.
Giải pháp khả dụng sau 3 lần thử
Review exercise
Find every word made up ONLY of consonants (no vowels, no digits, no symbols).
Hiển thị gợi ý
Inside the brackets you can combine vowel negation with \\W (non-word) and \\d (digits).
Giải pháp khả dụng sau 3 lần thử
Additional challenge
Match sequences of one or more characters, explicitly excluding whitespace and commas.
Hiển thị gợi ý
Use [^\s,] with the + quantifier.
Giải pháp khả dụng sau 3 lần thử