Stacking Arrays with Dask in Python 2026 – Best Practices
Dask provides da.stack() and da.concatenate() to combine multiple arrays along new or existing dimensions. Understanding when to use each is important for building efficient multidimensional workflows.
Examples
import dask.array as da
arr1 = da.random.random((1000, 500), chunks=(200, 500))
arr2 = da.random.random((1000, 500), chunks=(200, 500))
# Stack along a new axis (creates 3D array)
stacked = da.stack([arr1, arr2], axis=0)
# Concatenate along existing axis
concatenated = da.concatenate([arr1, arr2], axis=0)
Best Practices
- Use
da.stack()when creating a new dimension - Use
da.concatenate()when joining along an existing dimension - Rechunk after stacking/concatenating if needed
Conclusion
Proper use of stacking and concatenation helps build complex multidimensional arrays efficiently with Dask.
Next steps:
- Practice stacking multiple Dask Arrays in your workflows