# GH_ListUtil class

Namespace: [Grasshopper.Kernel](https://developer.rhino3d.com/api/gh1/namespace/grasshopper.kernel.md) · Assembly: [Grasshopper](https://developer.rhino3d.com/api/gh1/assembly/grasshopper.md)

```cs
public sealed class GH_ListUtil
```

Provides utilities for dealing with list of Data from input parameters.

## Methods

- [CountNonNullRefs<T>](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.gh-listutil/countnonnullrefs.md): (static) Count all object references in L
- [CountNullRefs<T>](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.gh-listutil/countnullrefs.md): (static) Count all null references in L
- [EnsureNonNullCount<T>](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.gh-listutil/ensurenonnullcount.md): (static) Tests a list to see if it contains sufficient non-null references.
- [FirstNonNullItem<T>](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.gh-listutil/firstnonnullitem.md): (static) Returns the index of the first non-null item in a list.
- [RemoveNullRefs<T>](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.gh-listutil/removenullrefs.md): (static) Remove all null references from a list of items.