字符串

1.截取字符串
NSString*string =@"sdfsfsfsAdfsdf";string = [string substringToIndex:7];//截取掉下标7之后的字符串NSLog(@"截取的值为：%@",string);[string substringFromIndex:2];//截取掉下标2之前的字符串NSLog(@"截取的值为：%@",string);

2.匹配字符串
NSString*string =@"sdfsfsfsAdfsdf";NSRangerange = [stringrangeOfString:@"f"];//匹配得到的下标NSLog(@"rang:%@",NSStringFromRange(range));string = [string substringWithRange:range];//截取范围类的字符串NSLog(@"截取的值为：%@",string);

3.分隔字符串NSString*string =@"sdfsfsfsAdfsdf";NSArray *array = [string componentsSeparatedByString:@"A"]; //从字符A中分隔成2个元素的数组NSLog(@"array:%@",array); //结果是adfsfsfs和dfsdf


-(BOOL) hasPrefix:(NSString *) astring;检查字符串是否以astring;   //判断是否开头
-(BOOL) hasSuffix:(NSString *) astring;检查字符串是否以astring;   //判断是否结尾