This is a working solution without taking care of some corner cases. Will this be clear on what I am doing? Do you have any suggestions on how to improve the efficiency of the code? Thanks!
torch.cat([first_embed, 
               torch.stack([
                    torch.cat([
                          _emb.expand(_s_len, 10), 
                          torch.zeros(PADDING_LEN - _s_len, 10, dtype=torch.float)]
                    , 0) 
                    for _s_len, _emb in zip(original_len, second_embed)]
               , 0)
, 2)

where first_embed is padding_data_1, data_1_len is original_len and second_embed is data_2 in previous replies.