Stacking Two-Dimensional Arrays with Dask in Python 2026
Stacking 2D Dask Arrays is commonly used when combining feature matrices or image batches.
Example
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 new axis (creates 3D)
stacked = da.stack([arr1, arr2], axis=0)
# Concatenate along existing axis
concatenated = da.concatenate([arr1, arr2], axis=0)
print("Stacked shape:", stacked.shape)
print("Concatenated shape:", concatenated.shape)
Best Practices
- Use
da.stack()to add a new dimension - Use
da.concatenate()to join along existing dimensions - Rechunk after stacking to maintain good performance
Conclusion
Stacking 2D arrays is a fundamental operation when building higher-dimensional datasets with Dask.
Next steps:
- Practice stacking multiple 2D arrays from your datasets