NSScanner使用方法

• 实例方法

- (NSString *)string;
- (NSUInteger)scanLocation;
- (void)setScanLocation:(NSUInteger)pos;//设置开始扫描的位置
- (void)setCharactersToBeSkipped:(NSCharacterSet *)set;//扫描的时候需要忽略的值
- (void)setCaseSensitive:(BOOL)flag; //是否区分大小写
- (void)setLocale:(id)locale; //大概意思是不同语言环境解释字符串的方式不一样，不懂
- (NSCharacterSet *)charactersToBeSkipped; //扫描时所有被忽略的值
- (BOOL)caseSensitive;
- (id)locale;

- (BOOL)scanInt:(int *)value;  //是否找到一个十进制 int
- (BOOL)scanInteger:(NSInteger *)value NS_AVAILABLE(10_5, 2_0);  //是否找到一个十进制 NSInteger
- (BOOL)scanHexLongLong:(unsigned long long *)result NS_AVAILABLE(10_5, 2_0);   //是否找到16进制的long long类型的数字
- (BOOL)scanHexFloat:(float *)result NS_AVAILABLE(10_5, 2_0);       // Corresponding to %a or %A formatting. Requires "0x" or "0X" prefix. 
- (BOOL)scanHexDouble:(double *)result NS_AVAILABLE(10_5, 2_0);     // Corresponding to %a or %A formatting. Requires "0x" or "0X" prefix. 
- (BOOL)scanHexInt:(unsigned *)value;       // Optionally prefixed with "0x" or "0X"
- (BOOL)scanLongLong:(long long *)value;
- (BOOL)scanFloat:(float *)value;
- (BOOL)scanDouble:(double *)value;

- (BOOL)scanString:(NSString *)string intoString:(NSString **)value; //从scan中扫描出set中的数据放入value中

- (BOOL)scanCharactersFromSet:(NSCharacterSet *)set intoString:(NSString **)value;//从scan中扫描出set中的数据放入value中
- (BOOL)scanUpToString:(NSString *)string intoString:(NSString **)value;//从scan中扫描出set之外的数据放入value中
- (BOOL)scanUpToCharactersFromSet:(NSCharacterSet *)set intoString:(NSString **)value;//从scan中扫描出set之外的数据放入value中
- (BOOL)isAtEnd;//是否扫描达到终点

- (id)initWithString:(NSString *)string;
+ (id)scannerWithString:(NSString *)string;
+ (id)localizedScannerWithString:(NSString *)string;

• 判断是否是int类型

 - (BOOL)isPureInt:(NSString*)string{    
              NSScanner* scanner = [NSScanner scannerWithString:string];    
              int intVal;    
              return [scanner scanInt:&intVal] && [scanner isAtEnd];
}

• 判断是否是float类型

 - (BOOL)isPureFloat:(NSString*)string{    
              NSScanner* scanner = [NSScanner scannerWithString:string];    
              float floatVal;    
              return [scanner scanFloat:&floatVal] && [scanner isAtEnd];
}

• 方法使用

NSString * numStr = @"a1b2c3d4e5f6“；
NSScanner * scanner = [NSScanner scannerWithString：numStr];
NSCharacterSet * numSet = [NSCharacterSet decimalDigitCharacterSet];
while （NO == [scanner isAtEnd]） {
  if （[scanner scanUpToCharacterFromSet：numSet intoString：NULL]） {
      int num;
    if （[scanner scanInt：&num]） {
        NSLog（@"num ： %d”，num）;
      }
}
}
结果是： num ： 1
        num ： 2
        num ： 3
        num ： 4
        num ： 5
        num ： 6

• 读取下一行

[scanner scanCharactersFromSet:[NSCharacterSet newlineCharacterSet]  intoString:NULL];