常用的正则表达式

转载：http://www.open-open.com/lib/view/open1390612242398.html

在 iOS 中，我们使用 NSPredicate 的字符串比较功能来进行正则表达式处理，其比较关键字为：MATCHES

下面是一些常用的正则表达式//邮箱  + (BOOL) validateEmail:(NSString *)email  {      NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";      NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];      return [emailTest evaluateWithObject:email];  }  //手机号码验证  + (BOOL) validateMobile:(NSString *)mobile  {      //手机号以13， 15，18开头，八个 \d 数字字符      NSString *phoneRegex = @"^((13[0-9])|(15[^4,\\D])|(18[0,0-9]))\\d{8}$";      NSPredicate *phoneTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",phoneRegex];      return [phoneTest evaluateWithObject:mobile];  }  //车牌号验证  + (BOOL) validateCarNo:(NSString *)carNo  {      NSString *carRegex = @"^[\u4e00-\u9fa5]{1}[a-zA-Z]{1}[a-zA-Z_0-9]{4}[a-zA-Z_0-9_\u4e00-\u9fa5]$";      NSPredicate *carTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",carRegex];      NSLog(@"carTest is %@",carTest);      return [carTest evaluateWithObject:carNo];  }  //车型  + (BOOL) validateCarType:(NSString *)CarType  {      NSString *CarTypeRegex = @"^[\u4E00-\u9FFF]+$";      NSPredicate *carTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",CarTypeRegex];      return [carTest evaluateWithObject:CarType];  }  //用户名  + (BOOL) validateUserName:(NSString *)name  {      NSString *userNameRegex = @"^[A-Za-z0-9]{6,20}+$";      NSPredicate *userNamePredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",userNameRegex];      BOOL B = [userNamePredicate evaluateWithObject:name];      return B;  }  //密码  + (BOOL) validatePassword:(NSString *)passWord  {      NSString *passWordRegex = @"^[a-zA-Z0-9]{6,20}+$";      NSPredicate *passWordPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",passWordRegex];      return [passWordPredicate evaluateWithObject:passWord];  }  //昵称  + (BOOL) validateNickname:(NSString *)nickname  {      NSString *nicknameRegex = @"^[\u4e00-\u9fa5]{4,8}$";      NSPredicate *passWordPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",nicknameRegex];      return [passWordPredicate evaluateWithObject:nickname];  }  //身份证号  + (BOOL) validateIdentityCard: (NSString *)identityCard  {      BOOL flag;      if (identityCard.length <= 0) {          flag = NO;          return flag;      }      NSString *regex2 = @"^(\\d{14}|\\d{17})(\\d|[xX])$";      NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];      return [identityCardPredicate evaluateWithObject:identityCard];  } 

其实iOS中有三种方式来实现正则表达式的匹配。现在将他们都记录在这里：
1.利用NSPredicate（谓词）匹配
例如匹配有效邮箱：
NSString ＊email ＝ @“[e-mail]”；
NSString *regex = @”[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}”;
NSPredicate *predicate = [NSPredicate predicateWithFormat:@”SELF MATCHES %@”, regex];
BOOL isValid = [predicate evaluateWithObject:email];
谓词匹配比较灵活，但是需要有谓词的相关知识。
2.利用rangeOfString：option：直接查找
NSString *searchText = @”// Do any additional setup after loading the view, typically from a nib.”;
NSRange range = [searchText rangeOfString:@”(?:[^,])*\.” options:NSRegularExpressionSearch];
if (range.location != NSNotFound) {
NSLog(@”%@”, [searchText substringWithRange:range]);
}
options中设定NSRegularExpressionSearch就是表示利用正则表达式匹配，会返回第一个匹配结果的位置。
3.使用正则表达式类
NSString *searchText = @”// Do any additional setup after loading the view, typically from a nib.”;
NSError *error = NULL;
NSRegularExpression regex = [NSRegularExpression regularExpressionWithPattern:@”(?:[^,])\.” options:NSRegularExpressionCaseInsensitive error:&error];
NSTextCheckingResult *result = [regex firstMatchInString:searchText options:0 range:NSMakeRange(0, [searchText length])];
if (result) {
NSLog(@”%@\n”, [searchText substringWithRange:result.range]);
}
使用系统的正则表达式类（NSRegularExpression）会返回匹配的多个结果。