What is regex character set?

With a “character class”, also called “character set”, you can tell the regex engine to match only one out of several characters. Simply place the characters you want to match between square brackets. If you want to match an a or an e, use [ae]. You could use this in gr[ae]y to match either gray or grey.

How do I match a character in regex?

Match any specific character in a set

1. Use square brackets [] to match any characters in a set.
2. Use \w to match any single alphanumeric character: 0-9 , a-z , A-Z , and _ (underscore).
3. Use \d to match any single digit.
4. Use \s to match any single whitespace character.

Is a special regex character?

In the regex flavors discussed in this tutorial, there are 12 characters with special meanings: the backslash \, the caret ^, the dollar sign $, the period or dot ., the vertical bar or pipe symbol |, the question mark ?, the asterisk or star *, the plus sign +, the opening parenthesis (, the closing parenthesis ), the …

How do you set a character in regexp?

With a “character class”, also called “character set”, you can tell the regex engine to match only one out of several characters. Simply place the characters you want to match between square brackets. If you want to match an a or an e, use [ae]. You could use this in gr[ae]y to match either gray or grey.

When to use sets and ranges in regexp?

Sets and ranges […] Several characters or character classes inside square brackets […] mean to “search for any character among given”. For instance, [eao] means any of the 3 characters: ‘a’, ‘e’, or ‘o’. That’s called a set. Sets can be used in a regexp along with regular characters:

How to match any character with regex in Java?

1 Match any character using regex ‘.’ character will match any character without regard to what character it is. 2 Match fixed set of characters using regex If we want to match a set of characters at any place, we need to use character classes. e.g. 3 Match range of characters using regex

How to find n or s in regular expressions?

To find n or s, you would not want to match any character, you would want to match just those two characters. In regular expressions a set of characters is defined using the metacharacters [ and ]. [ and ] define a character set, everything between them is part of the set, and any one of the set members must match (but not all).