数组按照首字母升序排列

将数组按照首字母英文升序排列'a'->'z'

+ (NSMutableArray *)ascendingOrderWithEnglishFirstChar:(NSArray *)sortArray{
    
    NSMutableArray *resultArray = [[NSMutableArray alloc] init];
    //sz : 首字母
    for (char sz = 'a'; sz <= 'z'; ++sz) {
        for (int i = 0; i < [sortArray count]; ++i) {
            // dKey : 单个的key
            NSString *dKey = sortArray[i];
            // dszm : 单个首字母
            NSString *dSzm = [dKey substringToIndex:1];
           // NSLog(@"单个Key：%@ \n key的首字母:%@",dKey,dSzm);
            if ([[NSString stringWithFormat:@"%c",sz] isEqualToString:dSzm]) {
                [resultArray addObject:dKey];
            }
        }
    }
    
    return resultArray;
}