iOS-Cocoa: 邮箱检查的正则表达式

NSString *emailPattern = @"^[-.0-9_\\p{letter}]+@[0-9\\p{letter}]+(\\.[-0-9_\\p{letter}]+)+$";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:emailPattern options:0 error:nil];
NSTextCheckingResult *match = [regex firstMatchInString:email options:0 range:NSMakeRange(0, [email length])];
if (match) {
//valid
}
else{
//invalid
}