dask.dataframe.Index.nunique_approx
dask.dataframe.Index.nunique_approx¶
- Index.nunique_approx(split_every=None)¶
Approximate number of unique rows.
This method uses the HyperLogLog algorithm for cardinality estimation to compute the approximate number of unique rows. The approximate error is 0.406%.
- Parameters
- split_everyint, optional
Group partitions into groups of this size while performing a tree-reduction. If set to False, no tree-reduction will be used. Default is 8.
- Returns
- a float representing the approximate number of elements