# dask.array.concatenate

dask.array.concatenate(seq, axis=0, allow_unknown_chunksizes=False)

  Concatenate arrays along an existing axis

  Given a sequence of dask Arrays form a new dask Array by stacking them along an existing dimension (axis=0 by default)

  Parameters:
    seq: list of dask.arrays
    axis: int

      Dimension along which to align all of the arrays. If axis is None, arrays are flattened before use.

    allow_unknown_chunksizes: bool

      Allow unknown chunksizes, such as come from converting from dask dataframes. Dask.array is unable to verify that chunks line up. If data comes from differently aligned sources then this can cause unexpected results.

  See also

  `stack`

  Examples

  Create slices

      >>> import dask.array as da
      >>> import numpy as np

      >>> data = [da.from_array(np.ones((4, 4)), chunks=(2, 2))
      ...          for i in range(3)]

      >>> x = da.concatenate(data, axis=0)
      >>> x.shape
      (12, 4)

      >>> da.concatenate(data, axis=1).shape
      (4, 12)

  Result is a new dask Array