# 05 Lists

This example shows you how to use lists in a blackboard.

These files can be found in the /Examples/\[example] and /Blackboards/Examples folders.

![Example 05 Lists editor](/files/lYK6wyBGvpph9E1BC1dF)

## ListBlackboard.cs

```csharp
using System.Collections.Generic;
using System.Linq;
using CrashKonijn.RabbitBlackboard.Contracts;

namespace CrashKonijn.BlackboardPro.Blackboards.Examples
{
    public partial class ListBlackboard : BlackboardBehaviour
    {
        private int startHealth = 100;

        // Lists can be of any type
        private List<int> changes;

        // This is a computed property, showing health being equal to startHealth plus the sum of all changes.
        private static int health(Signals.StartHealth startHealth, Signals.Changes changes) => startHealth.Value + changes.Value.Sum(x => x);
    }
}

```

## ListsHealthBehaviour.cs

```csharp
using CrashKonijn.RabbitBlackboard.Contracts;
using UnityEngine;
using ListBlackboard = CrashKonijn.BlackboardPro.Blackboards.Examples.ListBlackboard;

namespace CrashKonijn.BlackboardPro.Examples._05_lists
{
    [RequireComponent(typeof(ListBlackboard))]
    public class ListsHealthBehaviour : MonoBehaviour
    {
        /* Simple hack to show a button in the editor */
        [Header("Removes 10 health.")]
        [Button(nameof(DoDamage))]
        public string doDamageButton;

        /* Simple hack to show a button in the editor */
        [Header("Adds 10 health")]
        [Button(nameof(Heal))]
        public string healButton;

        /* Simple hack to show a button in the editor */
        [Header("Clears the changes list")]
        [Button(nameof(Clear))]
        public string clearButton;

        private ListBlackboard blackboard;

        public ListBlackboard Blackboard
        {
            get
            {
                if (this.blackboard == null)
                {
                    this.blackboard = this.GetComponent<ListBlackboard>();
                }

                return this.blackboard;
            }
        }

        public void DoDamage()
        {
            this.Blackboard.Changes.Add(-10);
        }

        public void Heal()
        {
            this.Blackboard.Changes.Add(10);
        }

        public void Clear()
        {
            this.Blackboard.Changes.Clear();
        }
    }
}

```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://blackboard.crashkonijn.com/examples/05_lists.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.