// Sets the transforms rotation to rotate 30 degrees around the y-axis
transform.rotation = Quaternion.AngleAxis(30, Vector3.up);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Example() {
        transform.rotation = Quaternion.AngleAxis(30, Vector3.up);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Example():
        transform.rotation = Quaternion.AngleAxis(30, Vector3.up)