iOS NSStringの一般的な方法

//               path         ,      enc, error     
+ (id)stringWithContentsOfURL:(NSURL *)url encoding:(NSStringEncoding)enc error:(NSError **)error;

//               url      ,      enc, error     
+ (id)stringWithContentsOfFile:(NSString *)path encoding:(NSStringEncoding)enc error:(NSError **)error;

//          
+(id)string;

//         ,        string   
+ (id)stringWithString:(NSString *)string;

//           astring   
- (id)initWithString:(NSString *)aString;

//       path               enc, error     
- (id)initWithContentsOfFile:(NSString *)path encoding:(NSStringEncoding)enc error:(NSError **)error;

//       path               enc, error     
- (id)initWithContentsOfURL:(NSURL *)url encoding:(NSStringEncoding)enc error:(NSError **)error;

//           
- (NSUInteger)length; 

//    (   ,  i)   Unicode        
- (unichar)characterAtIndex:(NSUInteger)index;

//   (?)          
- (NSString *)substringFromIndex:(NSUInteger)from;

//            (?)     
- (NSString *)substringToIndex:(NSUInteger)to;

//            
- (NSString *)substringWithRange:(NSRange)range; 

//        (     )
- (NSComparisonResult)caseInsensitiveCompare:(NSString *)string;

//       
- (NSComparisonResult)localizedCompare:(NSString *)string;

//        aString  
- (BOOL)hasPrefix:(NSString *)aString;

//        aString  
- (BOOL)hasSuffix:(NSString *)aString;

//           
- (BOOL)isEqualToString:(NSString *)aString;

//                   ,      
- (NSString *)capitalizedString;

//           
- (NSString *)lowercaseString;

//           
- (NSString *)uppercaseString;

//     UTF8        
- (__strong const char *)UTF8String;

//    double      
- (double)doubleValue;

//    float      
- (float)floatValue;

//    int      
- (int)intValue;

//     NSInteger      
- (NSInteger)integerValue;