Add a rolling_statistics

[RondeauG]

Addressing a Problem?

We already have statistics and thresholded_statistics, but a rolling_statistics would be very useful for anything related to hydrology and probably other domains too.

Use cases include for example computing the maximum 14-day mean flow (q14max), or the minimum 7-day mean flow (q7min).

Potential Solution

Possible code to be used:

def roll_stats(da: xr.DataArray, window: int, window_reducer: str, reducer: str, freq: str, **indexer) -> xr.DataArray:
    """Calculate a stat on a rolling stat."""
    rolled = getattr(da.rolling(time=window, center=True), window_reducer)()
    rolled_indexed = select_time(rolled, **indexer)
    out = getattr(rolled_indexed.resample(time=freq), reducer)()
    out.attrs["units"] = da.attrs["units"]  # on peut faire mieux
    return out

Additional context

No response

Contribution

• I would be willing/able to open a Pull Request to contribute this feature.

Code of Conduct

• I agree to follow this project's Code of Conduct

[Zeitsperre]

@RondeauG Still willing to contribute this?

[RondeauG]

Sorry I kinda abandoned this! Yes, I can contribute.