字符串

創(chuàng)建字符串

+ (id) stringWithFormat: (NSString *) format,...;//此處stringWithFormat:是一個工廠方法

NSString *height ; height= [NSString stringWithFormat:@"Your height is %d feet,%d feet, %d inches",5,11];

字符串比較

- (BOOL) osEqualToString:(NSString *)aString; //實例方法 比較兩個字符串內(nèi)容是否相同

NSString *thing1 = @"hello 5"; NSString *thing2=[NSString stringWithFormat: @"hello %d",5]; if([thing1 isEqualToString: thing2]) { NSLog(@"They are the same!"); }

- (NSComparisonResult) compare: (NSString *) aString;
//compare:將接收對象和傳遞過來的字符串逐個進行比較(區(qū)分大小寫)，顯示孰大孰小
//其返回類型為一個enum型枚舉，如下所示
  enum{
  NSOrderedAscending = -1,
  NSOrderedSame,
  NSOrderedDescending
  };
  typedef NSInteger NSComparisonResult;

不區(qū)分大小寫的比較

- (NSComparisonResult) compare: (NSString *) aString options: (NSStringCompareOptions) mask;
//其中常用的mask選項如下:
NSCaseInsensitiveSearch:不區(qū)分大小寫字符
NSLiteralSearch:進行完全比較，區(qū)分大小寫
NSNumericSearch:比較字符串的字符個數(shù)

字符串內(nèi)是否包含別的字符串

- (BOOL) hasPrefix: (NSString *) aString;
- (BOOL) hasSuffix: (NSString *) aString;
- (BOOL) rangOfString: (NSString *) aString;

可變性

+ (id) stringWithCapacity: (NSUInteger) capacity;
- (void) appendString: (NSString *) aString;
- (void) appendFormat: (NSString *) format, ...;
- (void) deleteCharactersInRange: (NSRange) aRange;