changing roatation of a 2d object in unity code example

Example 1: rotation unity script 2d

transform.eulerAngles = Vector3.forward * degrees;
// or
transform.rotation = Quaternion.Euler(Vector3.forward * degrees);
// or
transform.rotation = Quaternion.LookRotation(Vector3.forward, yAxisDirection);
// or
transform.LookAt(Vector3.forward, yAxisDirection);
// or
transform.right = xAxisDirection;
// or
transform.up = yAxisDirection;

Example 2: rotation unity script 2d

transform.Rotate(Vector3(0, 0, 50));
//instead of :
transform.eulerAngles = new Vector3 (0, 0, 50);
//or like you said
transform.eulerAngles = Vector3.forward * 50;