^ : Start of the line.(([^<>()[\]\\.,;:@"]+(\.[^<>()[\]\\.,;:@"]+)*)|(".+")) : This is the local part of the email, before the @ symbol. It can be one of two formats:
[^<>()[\]\\.,;:@"]+(\.[^<>()[\]\\.,;:@"]+)* : This means one or more characters that are not special characters (like <, >, (, ), [, ], \, ,, ;, :, @, ") followed by a period . and more non-special characters. This pattern can repeat.".+" : This means any characters surrounded by quotes.@ : This is the @ symbol in the email.((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,})) : This is the domain part of the email, after the @ symbol. It can be one of two formats:
\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\] : This is an IP address format, like [192.168.0.1].([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,} : This is a domain name format, like example.com. It means one or more alphanumeric characters or hyphens followed by a period ., and this pattern can repeat. It ends with two or more alphabetic characters.$ : End of the line.