Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Added dask data interface #974

merged 8 commits into from Nov 16, 2016

Added docstring for DaskInterface

  • Loading branch information...
Philipp Rudiger Philipp Rudiger
Philipp Rudiger authored and Philipp Rudiger committed Nov 5, 2016
commit b2857f5df63d75603f127d1394b1eaf8ddab3a52
Copy path View file
@@ -19,6 +19,23 @@

class DaskInterface(PandasInterface):
The DaskInterface allows a Dataset objects to wrap a dask
DataFrame object. Using dask allows loading data lazily
and performing out-of-core operations on the data, making
it possible to work on datasets larger than memory.
The DaskInterface covers almost the complete API exposed
by the PandasInterface with two notable exceptions:
1) Sorting is not supported and any attempt at sorting will
be ignored with an warning.
2) Dask does not easily support adding a new column to an existing
dataframe unless it is a scalar, add_dimension will therefore
error when supplied a non-scalar value.
4) Not all functions can be easily applied to a dask dataframe so
some functions applied with aggregate and reduce will not work.

types = (DataFrame,)

@@ -101,7 +118,6 @@ def select_mask(cls, dataset, selection):
def select(cls, columns, selection_mask=None, **selection):
df =
if selection_mask is not None:
print selection_mask
return df[selection_mask]
selection_mask = cls.select_mask(columns, selection)
indexed = cls.indexed(columns, selection)
@@ -197,7 +213,8 @@ def add_dimension(cls, columns, dimension, dim_pos, values, vdim):
data =
if not in data.columns:
if not np.isscalar(values):
err = 'Dask dataframe does not support assigning non-scalar value.'
err = ('Dask dataframe does not support assigning '
'non-scalar value.')
raise NotImplementedError(err)
data = data.assign(**{ values})
return data
ProTip! Use n and p to navigate between commits in a pull request.
You can’t perform that action at this time.