ml-agents/unity-environment/Assets/ML-Agents/Examples/Shared Assets/Scripts/RandomDecision.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class RandomDecision : MonoBehaviour, Decision
{
    BrainParameters brainParameters;
    SpaceType actionSpaceType;
    int actionSpaceSize;

    public void Awake()
    {
        brainParameters = 
            gameObject.GetComponent<Brain>().brainParameters;
        actionSpaceType = brainParameters.vectorActionSpaceType;
        actionSpaceSize = brainParameters.vectorActionSize;
    }

    public float[] Decide(List<float> state, List<Texture2D> observation, 
                          float reward, bool done, List<float> memory)
    {
        
        if (actionSpaceType == SpaceType.continuous)
        {
            List<float> act = new List<float>();

            for (int i = 0; i < actionSpaceSize; i++)
            {
                act.Add(2*Random.value-1);
            }

            return act.ToArray();
        }
        else
        {
            return new float[1] { Random.Range(0,actionSpaceSize)  };
        }
    }

    public List<float> MakeMemory(List<float> state,
                                  List<Texture2D> observation, float reward,
                                  bool done, List<float> memory)
    {
        return new List<float>();
    }
}