# forge.series.rolling

```python
forge.series.rolling(x: ArrayLike, window: int, how: Literal['mean', 'sum', 'min', 'max', 'std']) -> np.ndarray
```

The ``how`` of the last ``window`` values ending at each bar, NaN until ``window`` values
exist.

``how`` is ``"mean"``, ``"sum"``, ``"min"``, ``"max"`` or ``"std"`` (the population standard
deviation). A NaN inside a window gives NaN for it.

Since Forge API 1.