\) to match the character itself.// Example regex to match an email address
[\w.%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}
This regex will match an email address in the format username@domain.com.
// Example regex to match a phone number
\+?\d{1,3}[-. ]?\d{3}[-. ]?\d{4}
This regex will match a phone number in a variety of formats, including 123-456-7890, 123.456.7890, and +1 123-456-7890.
// Example regex to match a URL
https?://[\w\-\.]+(:\d+)?(/[\w/_\.]*)?
This regex will match a URL in a variety of formats, including http://www.example.com, https://example.com/path/to/page.html, and http://www.example.com:8080/path/to/page.html.
.: Matches any single character except a newline.^: Matches the start of a string.$: Matches the end of a string.*: Matches zero or more occurrences of the previous character.+: Matches one or more occurrences of the previous character.?: Matches zero or one occurrence of the previous character.|: Matches either the character on the left or the character on the right.[]: Matches any one character within the brackets.(): Groups characters together.\d: Matches any digit character.\w: Matches any word character (alphanumeric and underscore).\s: Matches any whitespace character.\D: Matches any non-digit character.\W: Matches any non-word character.\S: Matches any non-whitespace character.{n}: Matches exactly n occurrences of the previous character.{n,}: Matches n or more occurrences of the previous character.{n,m}: Matches between n and m occurrences of the previous character.(?=...)) and lookbehinds ((?<=...)) can be used to match characters based on what precedes or follows them.\1, \2, etc.) can be used to refer to previously matched groups.