How do I stop my walk animation playing, when my character is idle?

I am programming a walking script for a top-down perspective RPG.

All the walking animations play correctly when walking in each direction, but when the player is not walking, the animations for the west-facing walk ( wSprites) carry on playing. I'm not sure what's caused this.

Here is my code: thanks for your time!

 public class TopDownController : MonoBehaviour
 {
 
     public Rigidbody2D body;
     public SpriteRenderer SpriteRenderer;
 
     public List<Sprite> nSprites;
     public List<Sprite> neSprites;
     public List<Sprite> eSprites;
     public List<Sprite> seSprites;
     public List<Sprite> sSprites;
     public List<Sprite> swSprites;
     public List<Sprite> wSprites;
     public List<Sprite> nwSprites;
 
     public float walkSpeed;
 
     public float frameRate;
 
     float idleTime;
 
     Vector2 direction;
 
     void Start()
     {
         
     }
     void Update()
     {
         direction = new Vector2(Input.GetAxisRaw("Horizontal"), Input.GetAxisRaw("Vertical")).normalized;
 
         body.velocity = direction * walkSpeed;
 
         List<Sprite> directionSprites = GetSpriteDirection();
 
         if(directionSprites != null)
         {
             float playTime = Time.time - idleTime;
             int totalFrames = (int)(playTime * frameRate);
             int frame = totalFrames % directionSprites.Count;
 
             SpriteRenderer.sprite = directionSprites[frame];
         }
         else
         {
             idleTime = Time.time;
         }
     }
 
 
     List<Sprite> GetSpriteDirection()
     {
 
         List<Sprite> selectedSprites = null;
 
 
         if (direction.y > 0) //north
         {
             if (direction.x > 0)
             {
                 selectedSprites = neSprites;
             }
             else if (direction.x < 0)
             {
                 selectedSprites = nwSprites;
             }
             else
             {
                 selectedSprites = nSprites;
             }
         }
 
         else if (direction.y < 0) //south
         {
             if (direction.x > 0)
             {
                 selectedSprites = seSprites;
             }
             else if (direction.x < 0)
             {
                 selectedSprites = swSprites;
             }
             else
             {
                 selectedSprites = sSprites;
             }
         }
         else // neutral
         {
             if (direction.x > 0)
             {
                 selectedSprites = eSprites;
             }
             else
             {
                 selectedSprites = wSprites;
             }
         }
 
         return selectedSprites;
 
     }
 
 }