NSCharacter​Set 使用说明

NSCharacter​Set 和 NSMutableCharacterSet  用面向对象的方式来表示一组Unicode字符，它经常与NSString及NSScanner组合起来使用，在不同的字符上做过滤、删除或者分割操作。为了给你提供这些字符是哪些字符的直观印象，请看看NSCharacterSet 提供的类方法

• alphanumericCharacterSet
• capitalizedLetterCharacterSet
• controlCharacterSet
• decimalDigitCharacterSet
• decomposableCharacterSet
• illegalCharacterSet
• letterCharacterSet
• lowercaseLetterCharacterSet
• newlineCharacterSet
• nonBaseCharacterSet
• punctuationCharacterSet
• symbolCharacterSet
• uppercaseLetterCharacterSet
• whitespaceAndNewlineCharacterSet
• whitespaceCharacterSet

我们使用下边的方法 打印看看这些方法

 void dumpCharacterSet( NSString *name )
 {
     unichar idx;
     NSCharacterSet *cset = [NSCharacterSet performSelector: NSSelectorFromString(name)];
 
     printf("Character set (0-127): %s\n7-Bit: ", [name UTF8String]);
 
     for( idx = ; idx < ; idx++ )
     {
         if (  == idx ) {
             printf( "\n8-Bit: " );
         }
 
         //Returns a Boolean value that indicates whether a given character is in the receiver.
         if ([cset characterIsMember: idx])
         {
             //判断字符c是否为可打印字符（含空格）
             if ( isprint(idx) ) {
                 printf( "%c ", idx);
             }
             else {
                 printf( "%02x ", idx);
             }
         }
     }
     printf("\n\n");
 }

 // Reference output...
     dumpCharacterSet( @"alphanumericCharacterSet" );
     dumpCharacterSet( @"controlCharacterSet" );
     dumpCharacterSet( @"decimalDigitCharacterSet" );
     dumpCharacterSet( @"decomposableCharacterSet" );
     dumpCharacterSet( @"illegalCharacterSet" );
     dumpCharacterSet( @"letterCharacterSet" );
     dumpCharacterSet( @"lowercaseLetterCharacterSet" );
     dumpCharacterSet( @"nonBaseCharacterSet" );
     dumpCharacterSet( @"punctuationCharacterSet" );
     dumpCharacterSet( @"uppercaseLetterCharacterSet" );
     dumpCharacterSet( @"whitespaceAndNewlineCharacterSet" );
     dumpCharacterSet( @"whitespaceCharacterSet" );

打印结果如下

Character set (-): alphanumericCharacterSet
-Bit:           A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i j k l m n o p q r s t u v w x y z
-Bit: aa b2 b3 b5 b9 ba bc bd be c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d8 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f8 f9 fa fb fc fd fe ff 
 
Character set (-): controlCharacterSet
-Bit:           0a 0b 0c 0d 0e 0f           1a 1b 1c 1d 1e 1f 7f
-Bit:           8a 8b 8c 8d 8e 8f           9a 9b 9c 9d 9e 9f ad 
 
Character set (-): decimalDigitCharacterSet
-Bit:
-Bit: 
 
Character set (-): decomposableCharacterSet
-Bit:
-Bit: c0 c1 c2 c3 c4 c5 c7 c8 c9 ca cb cc cd ce cf d1 d2 d3 d4 d5 d6 d9 da db dc dd e0 e1 e2 e3 e4 e5 e7 e8 e9 ea eb ec ed ee ef f1 f2 f3 f4 f5 f6 f9 fa fb fc fd ff 
 
Character set (-): illegalCharacterSet
-Bit:
-Bit: 
 
Character set (-): letterCharacterSet
-Bit: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i j k l m n o p q r s t u v w x y z
-Bit: aa b5 ba c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d8 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f8 f9 fa fb fc fd fe ff 
 
Character set (-): lowercaseLetterCharacterSet
-Bit: a b c d e f g h i j k l m n o p q r s t u v w x y z
-Bit: b5 df e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f8 f9 fa fb fc fd fe ff 
 
Character set (-): nonBaseCharacterSet
-Bit:
-Bit: 
 
Character set (-): punctuationCharacterSet
-Bit: ! " # % & ' ( ) * , - . / : ; ? @ [ \ ] _ { }
-Bit: a1 a7 ab b6 b7 bb bf 
 
Character set (-): uppercaseLetterCharacterSet
-Bit: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
-Bit: c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d8 d9 da db dc dd de 
 
Character set (-): whitespaceAndNewlineCharacterSet
-Bit:  0a 0b 0c 0d
-Bit:  a0 
 
Character set (-): whitespaceCharacterSet
-Bit:
-Bit: a0 

非常的直观，当我们 使用的时候对照这个打印结果操作就行，

下边再说一下如何过滤的

 // Set up for reading testString
     NSString *testString = @"Los Angeles;8.25;0.580561574;1,Tokyo;1.9;0.643872234;1;Honolulu,0;0;0;Toronto;7.9;5.3322;3;";
     // Parse CSV with NSScanner
     NSScanner *myScanner = [NSScanner scannerWithString:testString];
 
     NSString    *location;
     float        theRevenue;
     float        thePercent;
     int            theRank;
 
     // Set up data delimiter using semicolon//分号
 
     NSCharacterSet *CharacterSet;
 
     //Returns a character set containing the characters in a given string.
     CharacterSet = [NSCharacterSet characterSetWithCharactersInString:@";,"];
 
     // Double check scanner string
     NSLog (@"Scanner string\n");
 
     //Returns the string with which the receiver was created or initialized.
     NSLog (@"%@",[myScanner string]);
 
     // scanner loop start
     while ([myScanner isAtEnd] == NO) {
 
         if ( [myScanner scanUpToCharactersFromSet:CharacterSet intoString:&location] ) {
             NSLog (@"%@",location);
         }
 
         // Skipping the ; and ,delimiter
         if([myScanner scanString:@";" intoString:NULL] || [myScanner scanString:@"," intoString:NULL])
             ;
         // Read Revenue data up to ; delimiter and skipping
         //Scans for a float value, returning a found value by reference.
         if([myScanner scanFloat:&theRevenue])
             NSLog(@"%lf",theRevenue);
         if([myScanner scanString:@";" intoString:NULL] || [myScanner scanString:@"," intoString:NULL])
             ;
 
         // Read Percentage data up to ; delimiter and skipping
         if([myScanner scanFloat:&thePercent])
             NSLog(@"%lf",thePercent);
         if([myScanner scanString:@";" intoString:NULL] || [myScanner scanString:@"," intoString:NULL])
             ;
 
         // Read Ranking data up to ; delimiter and skipping
         if([myScanner scanInt:&theRank])
             NSLog(@"%i",theRank);
         if([myScanner scanString:@";" intoString:NULL] || [myScanner scanString:@"," intoString:NULL])
             ;
     }

打印结果如下

-- ::37.967 ModelBenchmark[:] Los Angeles
-- ::37.967 ModelBenchmark[:] 8.250000
-- ::37.967 ModelBenchmark[:] 0.580562
-- ::37.968 ModelBenchmark[:]
-- ::37.968 ModelBenchmark[:] Tokyo
-- ::37.968 ModelBenchmark[:] 1.900000
-- ::37.968 ModelBenchmark[:] 0.643872
-- ::37.968 ModelBenchmark[:]
-- ::37.968 ModelBenchmark[:] Honolulu
-- ::37.968 ModelBenchmark[:] 0.000000
-- ::37.968 ModelBenchmark[:] 0.000000
-- ::37.968 ModelBenchmark[:]
-- ::37.968 ModelBenchmark[:] Toronto
-- ::37.968 ModelBenchmark[:] 7.900000
-- ::37.969 ModelBenchmark[:] 5.332200
-- ::37.969 ModelBenchmark[:] 

不难看出，对字符串的过滤非常灵活，因此我们应该使用这种方法来过滤字符串。