iOS中有三種方式來實現正則表達式的匹配。現在將他們都記錄在這裡：

1.利用NSPredicate（謂詞）匹配
例如匹配有效郵箱：

NSString ＊email ＝ @“[email protected]”； 
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];

謂詞匹配比較靈活，但是需要有謂詞的相關知識。

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中設定NSRegularExpressionSearch就是表示利用正則表達式匹配，會返回第一個匹配結果的位置。

3.使用正則表達式類

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]);
}

使用系統的正則表達式類（NSRegularExpression）會返回匹配的多個結果。

實例：
1.驗證郵箱

+ (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];
}

NSPredicate是一個Foundation類，是用來查詢的，原理和用法都類似於SQL中的where。

2.驗證手機號

簡單的判斷方法

+ (BOOL)validatePhone:(NSString *)phone
{
  NSString *phoneRegex = @"1[3|5|7|8|][0-9]{9}";
  NSPredicate *phoneTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", phoneRegex];
  return [phoneTest evaluateWithObject:phone];
}

這只是簡單地判斷手機號格式。其實手機的格式還是有一點復雜的。

詳細的判斷方法

//正則判斷手機號碼格式
+ (BOOL)validatePhone:(NSString *)phone
{
    /**
    * 手機號碼
    * 移動：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
    * 聯通：130,131,132,152,155,156,185,186
    * 電信：133,1349,153,180,189
    */
    NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
    /**
         * 中國移動：China Mobile
         * 134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
         */
    NSString * CM = @"^1(34[0-8]|(3[5-9]|5[017-9]|8[278])\\d)\\d{7}$";
    /**
         * 中國聯通：China Unicom
         * 130,131,132,152,155,156,185,186
         */
    NSString * CU = @"^1(3[0-2]|5[256]|8[56])\\d{8}$";
    /**
         * 中國電信：China Telecom
         * 133,1349,153,180,189
         */
    NSString * CT = @"^1((33|53|8[09])[0-9]|349)\\d{7}$";
    /**
         * 大陸地區固話及小靈通
         * 區號：010,020,021,022,023,024,025,027,028,029
         * 號碼：七位或八位
         */
   // NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";

   NSPredicate *regextestmobile = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", MOBILE];
   NSPredicate *regextestcm = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CM];
   NSPredicate *regextestcu = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CU];
   NSPredicate *regextestct = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CT];

  if (([regextestmobile evaluateWithObject:phone] == YES)
  || ([regextestcm evaluateWithObject:phone] == YES)
  || ([regextestct evaluateWithObject:phone] == YES)
  || ([regextestcu evaluateWithObject:phone] == YES))
  {
    if([regextestcm evaluateWithObject:phone] == YES) {
     NSLog(@"China Mobile");
    } else if([regextestct evaluateWithObject:phone] == YES) {
     NSLog(@"China Telecom");
    } else if ([regextestcu evaluateWithObject:phone] == YES) {
     NSLog(@"China Unicom");
    } else {
     NSLog(@"Unknow");
    }

    return YES;
  }
  else 
  {
    return NO;
  }
}