Matching Specific Characters
The character class [ ] matches only one out of several characters placed inside the square brackets.
Task
1203x.
1 | ^[123][120][xs0][30Aa][xsu][\.\,]$ |
Excluding Specific Characters
The negated character class [^] matches any character that is not in the square brackets.
Task
think?
1 | ^[^\d][^aeiou][^bcDF][^\s][^AEIOU][^\.\,]$ |
Matching Character Ranges
In the context of a regular expression (RegEx), a character class is a set of characters enclosed within square brackets that allows you to match one character in the set.
A hyphen (-) inside a character class specifies a range of characters where the left and right operands are the respective lower and upper bounds of the range. For example:
- [a-z] is the same as [abcdefghijklmnopqrstuvwxyz]
- [A-Z] is the same as [ABCDEFGHIJKLMNOPQRSTUVWXYZ]
- [0-9] is the same as [0123456789]
In addition, if you use a caret (^) as the first character inside a character class, it will match anything that is not in that range. For example, [^0-9] matches any character that is not a digit in the inclusive range from 0 to 9.
It’s important to note that, when used outside of (immediately preceding) a character or character class, the caret matches the first character in the string against that character or set of characters.
Task
h4CkR
1 | ^[a-z][1-9][^a-z][^A-Z][A-Z]* |