# skbio.alignment.TabularMSA.extend

`TabularMSA.``extend`(sequences, minter=None, index=None)

  Extend this MSA with sequences without recomputing alignment.

  State: Experimental as of 0.4.1.

  Parameters:

  sequences : iterable of IUPACSequence

  > Sequences 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 index labels for the sequences 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 : pd.Index consumable, optional

  > Index labels to use for the appended sequences. Must be the same length as sequences. Must be able to be passed directly to `pd.Index` constructor. Note that index cannot be combined with minter.

  Raises:

  ValueError

  > If both minter and index are both provided.

  ValueError

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

  ValueError

  > If index is not the same length as sequences.

  TypeError

  > If sequences contains an object that isn’t an `IUPACSequence`.

  TypeError

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

  ValueError

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

  See also

  `append`, `reassign_index`

  Notes

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

  The MSA is not automatically re-aligned when appending sequences. 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.extend([DNA('AG-T'), DNA('-G-T')])
      >>> msa
      TabularMSA[DNA]
      ---------------------
      Stats:
          sequence count: 3
          position count: 4
      ---------------------
      ACGT
      AG-T
      -G-T

  Auto-incrementing index labels:

      >>> msa.index
      Int64Index([0, 1, 2], dtype='int64')
      >>> msa.extend([DNA('ACGA'), DNA('AC-T'), DNA('----')])
      >>> msa.index
      Int64Index([0, 1, 2, 3, 4, 5], dtype='int64')