GameObject.GetComponentCount

Returns

int The number of components on the GameObject as an Integer value.

Description

Retrieves the total number of components currently attached to the GameObject.

You can use GetComponentCount to iterate through component indices, which is especially convenient if used together with GameObject.GetComponentAtIndex. For example, you can iterate through the indices to find the index of a particular component you're interested in and then save the index for later use.

using UnityEngine;

public class IterateComponents : MonoBehaviour
{
int m_SavedComponentIndex = -1;

    void Start()
    {
        //Iterate through components  on the GameObject
        for (int i = 0; i < gameObject.GetComponentCount(); i++)
        {
            var currComponent = gameObject.GetComponentAtIndex(i);
            
            //Check if it is a Rigidbody component
            if (currComponent.GetType() == typeof(Rigidbody) )
            {
                m_SavedComponentIndex = i;
            }
        }

        Debug.Log(m_SavedComponentIndex != -1 ? $"Found component at index: {m_SavedComponentIndex}" : "Could not find component");
    }
}

Additional resources: GameObject.GetComponentAtIndex