# forge.ta.isna

```python
forge.ta.isna(x: ArrayLike | float | None) -> np.ndarray[Any, np.dtype[np.bool_]] | bool
```

True where a value is missing: ``None`` or ``NaN``.

An array gives an array of the same shape. Boolean and integer arrays carry no
missing value (contract C3 section 2), so they give all ``False``.

Since Forge API 1.