# skbio.alignment.TabularMSA.append

`TabularMSA.``append`(sequence, minter=None, index=None)

  Append a sequence to the MSA without recomputing alignment.

  State: Experimental as of 0.4.1.

  Parameters:

  sequence : IUPACSequence

  > Sequence to be appended. Must match the dtype of the MSA and the number of positions in the MSA.

  minter : callable or metadata key, optional

  > Used to create an index label for the sequence being appended. If callable, it generates a label directly. Otherwise it’s treated as a key into the sequence metadata. Note that minter cannot be combined with index.

  index : object, optional

  > Index label to use for the appended sequence. Note that index cannot be combined with minter.

  Raises:

  ValueError

  > If both minter and index are provided.

  ValueError

  > If neither minter nor index are provided and the MSA has a non-default index.

  TypeError

  > If the sequence object isn’t an `IUPACSequence`.

  TypeError

  > If the type of the sequence does not match the dtype of the MSA.

  ValueError

  > If the length of the sequence does not match the number of positions in the MSA.

  See also

  `extend`, `reassign_index`

  Notes

  If neither minter nor index are provided and this MSA has default index labels, the new index label will be auto-incremented.

  The MSA is not automatically re-aligned when a sequence is appended. Therefore, this operation is not necessarily meaningful on its own.

  Examples

      >>> from skbio import DNA, TabularMSA
      >>> msa = TabularMSA([DNA('ACGT')])
      >>> msa
      TabularMSA[DNA]
      ---------------------
      Stats:
          sequence count: 1
          position count: 4
      ---------------------
      ACGT
      >>> msa.append(DNA('AG-T'))
      >>> msa
      TabularMSA[DNA]
      ---------------------
      Stats:
          sequence count: 2
          position count: 4
      ---------------------
      ACGT
      AG-T

  Auto-incrementing index labels:

      >>> msa.index
      Int64Index([0, 1], dtype='int64')
      >>> msa.append(DNA('ACGA'))
      >>> msa.index
      Int64Index([0, 1, 2], dtype='int64')