The expanding function’s apply function.

param func

Must produce a single value from an ndarray input if raw=True or a single value from a Series if raw=False.

param raw
bool, default None
  • Falsepasses each row or column as a Series to the


  • True or Nonethe passed function will receive ndarray

    objects instead. If you are just applying a NumPy reduction function this will achieve much better performance.

The raw parameter is required and will show a FutureWarning if not passed. In the future raw will default to False.

New in version 0.23.0.

Arguments and keyword arguments to be passed into func.


Series or DataFrame Return type is determined by the caller.


This feature is currently unsupported by Intel Scalable Dataframe Compiler