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iOS中使用正則表達式NSRegularExpression 來驗證textfiled輸入的內(nèi)容

何謂正則表達式

正則表達式（regular expression），在計算機科學中，是指一個用來描述或者匹配一系列符合某個句法規(guī)則的字符串的單個字符串。在很多文本編輯器或其他工具里，正則表達式通常被用來檢索和/或替換那些符合某個模式的文本內(nèi)容。正則表達式這個概念最初是由Unix中的工具軟件（例如sed和grep）普及開的。正則表達式通?？s寫成“regex”，單數(shù)有regexp、regex，復數(shù)有regexps、regexes、regexen。

正則表達式組成

正則表達式有兩種類型的字符組成

第一種：用來匹配的字符，或者叫常規(guī)字符

第二種：控制字符或具有特殊含義的元字符

iphone 4.0以后就開始支持正則表達式的使用了，在ios4.0中正則表達式的使用是使用NSRegularExpression類來調(diào)用。

1. 下面一個簡單的使用正則表達式的一個例子：NSRegularExpression 類

-(void)parseString{
//組裝一個字符串，需要把里面的網(wǎng)址解析出來
NSString *urlString=@"sfdsfhttp://www.baidu.com";
//NSRegularExpression類里面調(diào)用表達的方法需要傳遞一個NSError的參數(shù)。下面定義一個
 NSError *error;
//http+:[^\\s]* 這個表達式是檢測一個網(wǎng)址的。
  NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"http+:[^\\s]*" options:0 error:error];
  if (regex != nil) {
  NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlString options:0range:NSMakeRange(0, [urlString length])];
  if (firstMatch) {
   NSRange resultRange = [firstMatch rangeAtIndex:0]; //等同于 firstMatch.range --- 相匹配的范圍
   //從urlString當中截取數(shù)據(jù)
  NSString *result=[urlString substringWithRange:resultRange];
  //輸出結果
  NSLog(@"%@",result);
  }
  }
}

2.使用正則表達式來判斷

//初始化一個NSRegularExpression 對象，并設置檢測對象范圍為：0-9 
NSRegularExpression *regex2 = [NSRegularExpression regularExpressionWithPattern:@"^[0-9]*$" options:0 error:nil];
    if (regex2)
    {//對象進行匹配
       NSTextCheckingResult *result2 = [regex2 firstMatchInString:textField.text options:0 range:NSMakeRange(0, [textField.text length])];
      if (result2) {
      }
}

1.判斷郵箱格式是否正確的代碼：NSPredicatel類

//利用正則表達式驗證

NSPredicatel類:主要用來指定過濾器的條件,該對象可以準確的描述所需條件，對每個對象通過謂詞進行篩選，判斷是否與條件相匹配。謂詞是指在計算機中表示計算真假值的函數(shù)。原理和用法都類似于SQL查詢中的where，作用相當于數(shù)據(jù)庫的過濾取。主要用于從集合中分揀出符合條件的對象，也可以用于字符串的正則匹配

-(BOOL)isValidateEmail:(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];
}

2.匹配9-15個由字母/數(shù)字組成的字符串的正則表達式：

  NSString * regex = @"^[A-Za-z0-9]{9,15}$";
  NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
  BOOL isMatch = [pred evaluateWithObject:txtfldPhoneNumber.text];

Cocoa用NSPredicate描述查詢的方式，原理類似于在數(shù)據(jù)庫中進行查詢

用BETWEEN，IN，BEGINWITH，ENDWITH，CONTAINS，LIKE這些謂詞來構造NSPredicate，必要的時候使用SELF直接對自己進行匹配

//基本的查詢 
NSPredicate *predicate; 
predicate = [NSPredicate predicateWithFormat: @"name == 'Herbie'"]; 
  BOOL match = [predicate evaluateWithObject: car]; 
  NSLog (@"%s", (match) ? "YES" : "NO"); 
//在整個cars里面循環(huán)比較 
  predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"]; 
  NSArray *cars = [garage cars]; 
  for (Car *car in [garage cars]) { 
    if ([predicate evaluateWithObject: car]) { 
      NSLog (@"%@", car.name); 
    } 
  } 
//輸出完整的信息 
  predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"]; 
  NSArray *results; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
//含有變量的謂詞 
  NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:@"name == $NAME"]; 
  NSDictionary *varDict; 
  varDict = [NSDictionary dictionaryWithObjectsAndKeys: 
        @"Herbie", @"NAME", nil]; 
  predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict]; 
  NSLog(@"SNORGLE: %@", predicate); 
  match = [predicate evaluateWithObject: car]; 
 NSLog (@"%s", (match) ? "YES" : "NO"); 
//注意不能使用$VARIABLE作為路徑名，因為它值代表值 
//謂詞字符竄還支持c語言中一些常用的運算符 
  predicate = [NSPredicate predicateWithFormat: 
         @"(engine.horsepower > 50) AND (engine.horsepower  200)"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"oop %@", results); 
  predicate = [NSPredicate predicateWithFormat: @"name  'Newton'"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", [results valueForKey: @"name"]); 
//強大的數(shù)組運算符 
  predicate = [NSPredicate predicateWithFormat: 
         @"engine.horsepower BETWEEN { 50, 200 }"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
  NSArray *betweens = [NSArray arrayWithObjects: 
             [NSNumber numberWithInt: 50], [NSNumber numberWithInt: 200], nil]; 
  predicate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN %@", betweens]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
  predicateTemplate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN $POWERS"]; 
  varDict = [NSDictionary dictionaryWithObjectsAndKeys: betweens, @"POWERS", nil]; 
  predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
//IN運算符 
  predicate = [NSPredicate predicateWithFormat: @"name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", [results valueForKey: @"name"]); 
  predicate = [NSPredicate predicateWithFormat: @"SELF.name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", [results valueForKey: @"name"]); 
  names = [cars valueForKey: @"name"]; 
  predicate = [NSPredicate predicateWithFormat: @"SELF IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"]; 
  results = [names filteredArrayUsingPredicate: predicate];//這里限制了SELF的范圍 
  NSLog (@"%@", results); 
//BEGINSWITH,ENDSWITH,CONTAINS 
//附加符號，[c],[d],[cd],c表示不區(qū)分大小寫，d表示不區(qū)分發(fā)音字符，cd表示什么都不區(qū)分 
  predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'Bad'"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
  predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'HERB'"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
  predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH[cd] 'HERB'"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
//LIKE運算符（通配符） 
  predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '*er*'"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
  predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '???er*'"]; 
  results = [cars filteredArrayUsingPredicate: predicate]; 
  NSLog (@"%@", results); 
//基本的查詢
NSPredicate *predicate;
predicate = [NSPredicate predicateWithFormat: @"name == 'Herbie'"];
  BOOL match = [predicate evaluateWithObject: car];
  NSLog (@"%s", (match) ? "YES" : "NO");
//在整個cars里面循環(huán)比較
  predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
  NSArray *cars = [garage cars];
  for (Car *car in [garage cars]) {
    if ([predicate evaluateWithObject: car]) {
      NSLog (@"%@", car.name);
    }
  }
//輸出完整的信息
  predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
  NSArray *results;
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
//含有變量的謂詞
  NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:@"name == $NAME"];
  NSDictionary *varDict;
  varDict = [NSDictionary dictionaryWithObjectsAndKeys:
        @"Herbie", @"NAME", nil];
  predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
  NSLog(@"SNORGLE: %@", predicate);
  match = [predicate evaluateWithObject: car];
 NSLog (@"%s", (match) ? "YES" : "NO");
//注意不能使用$VARIABLE作為路徑名，因為它值代表值
//謂詞字符竄還支持c語言中一些常用的運算符
  predicate = [NSPredicate predicateWithFormat:
         @"(engine.horsepower > 50) AND (engine.horsepower  200)"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"oop %@", results);
  predicate = [NSPredicate predicateWithFormat: @"name  'Newton'"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", [results valueForKey: @"name"]);
//強大的數(shù)組運算符
  predicate = [NSPredicate predicateWithFormat:
         @"engine.horsepower BETWEEN { 50, 200 }"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
  NSArray *betweens = [NSArray arrayWithObjects:
             [NSNumber numberWithInt: 50], [NSNumber numberWithInt: 200], nil];
  predicate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN %@", betweens];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
  predicateTemplate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN $POWERS"];
  varDict = [NSDictionary dictionaryWithObjectsAndKeys: betweens, @"POWERS", nil];
  predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
//IN運算符
  predicate = [NSPredicate predicateWithFormat: @"name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", [results valueForKey: @"name"]);
  predicate = [NSPredicate predicateWithFormat: @"SELF.name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", [results valueForKey: @"name"]);
  names = [cars valueForKey: @"name"];
  predicate = [NSPredicate predicateWithFormat: @"SELF IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];
  results = [names filteredArrayUsingPredicate: predicate];//這里限制了SELF的范圍
  NSLog (@"%@", results);
//BEGINSWITH,ENDSWITH,CONTAINS
//附加符號，[c],[d],[cd],c表示不區(qū)分大小寫，d表示不區(qū)分發(fā)音字符，cd表示什么都不區(qū)分
  predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'Bad'"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
  predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'HERB'"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
  predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH[cd] 'HERB'"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
//LIKE運算符（通配符）
  predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '*er*'"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);
  predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '???er*'"];
  results = [cars filteredArrayUsingPredicate: predicate];
  NSLog (@"%@", results);

以上就是小編給大家分享的iOS中使用正則表達式NSRegularExpression 來驗證textfiled輸入的內(nèi)容，希望大家喜歡。

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