最近專案中有個客戶列表，需要對客戶（Customer）做字典序排列且按A~Z~#分組展示。下面記錄了我的實現方法（如果你有更好的方法，請不吝分享）：

 for (int i = 0; i < [arr count]; i++)
    {
        Customer *cstr= arr[i];
        NSString *firstLetter = [[NSString stringWithFormat:@"%c",[cstr.phonetic characterAtIndex:0]] uppercaseString];
        NSString *key = [AtoZ containsObject:firstLetter] ? firstLetter : @"#";

        NSMutableArray *arrStartWithKey = mDic[key];
        if (!arrStartWithKey) {
            arrStartWithKey = [[NSMutableArray alloc] init];
            [mDic setObject:arrStartWithKey forKey:key];
            [arrStartWithKey release];
        }
        [arrStartWithKey addObject:cstr];
    }