tableview的索引值

NSMutableArray *siftArray = [NSMutableArray
array];

NSArray *sources =
@[@"dfersa",@"adfae",@"frdg",@"rfde",@"drgs",@"wser",@"rfdt",@"pkoi"];

//    [self.sources addObjectsFromArray : [JKCountryResout searchCountryNameByStrings:@"china"]];

for (NSString *str
in self.sources){

NSString *resoultStr = [str
substringToIndex:1];

[siftArray
addObject:resoultStr];

}

NSSet *set = [NSSet
setWithArray:siftArray];

NSArray *sortDesc =
@[[[NSSortDescriptor
alloc] initWithKey:nil
ascending:YES]];

NSArray *sortSetArray = [set
sortedArrayUsingDescriptors:sortDesc];

NSLog(@"排序的结果 %@", sortSetArray);