Debug.Log

Parameters

Description

Logs a message to the Unity Console.

Use Debug.Log to print informational messages that help you debug your application. For example, you could print a message containing a GameObject.name and information about the object’s current state.

You can format messages with string concatenation:
Debug.Log("Text: " + myText.text);

You can also use Rich Text markup.

If you pass a GameObject or Component as the optional context parameter, Unity momentarily highlights that object in the Hierarchy window when you click the log message in the Console. Use a context object when you have many instances of an object in a Scene so that you can identify which one produced the message. Example 2, below, illustrates how this feature works. When you run this example, first click one of the cubes it creates in the Scene. The example prints a log message to the Console. When you click on the message, Unity highlights the context object in the Hierarchy window — in this case, the cube you clicked on in the Scene.

Example 1: Show some uses of Debug.Log:

using UnityEngine;
using System.Collections;

public class MyGameClass : MonoBehaviour
{
    // A Light used in the Scene and needed by MyGameMethod().
    public Light light;

    void MyGameMethod()
    {
        // Message with a GameObject name.
        Debug.Log("Hello: " + gameObject.name);

        // Message with light type. This is an Object example.
        Debug.Log(light.type);

        // Message using rich text.
        Debug.Log("<color=red>Error: </color>AssetBundle not found");
    }
}

Example 2: Show selection of a clicked GameObject:

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

// Debug.Log example
//
// Create three cubes. Place them around the world origin.
// If a cube is clicked use Debug.Log to announce it. Use
// Debug.Log with two arguments. Argument two allows the
// cube to be automatically selected in the hierarchy when
// the console message is clicked.
//
// Add this script to an empty GameObject.

public class Example : MonoBehaviour
{
    private GameObject[] cubes;

    void Awake()
    {
        // Create three cubes and place them close to the world space center.
        cubes = new GameObject[3];
        float f = 25.0f;
        float p = -2.0f;
        float[] z = new float[] {0.5f, 0.0f, 0.5f};

        for (int i = 0; i < 3; i++)
        {
            // Position and rotate each cube.
            cubes[i] = GameObject.CreatePrimitive(PrimitiveType.Cube);
            cubes[i].name = "Cube" + (i + 1).ToString();
            cubes[i].transform.Rotate(0.0f, f, 0.0f);
            cubes[i].transform.position = new Vector3(p, 0.0f, z[i]);
            f -= 25.0f;
            p = p + 2.0f;
        }

        // Position and rotate the camera to view all three cubes.
        Camera.main.transform.position = new Vector3(3.0f, 1.5f, 3.0f);
        Camera.main.transform.localEulerAngles = new Vector3(25.0f, -140.0f, 0.0f);
    }

    void Update()
    {
        // Process a mouse button click.
        if (Input.GetMouseButtonDown(0))
        {
            var ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;

            if (Physics.Raycast(ray, out hit))
            {
                // Visit each cube and determine if it has been clicked.
                for (int i = 0; i < 3; i++)
                {
                    if (hit.collider.gameObject == cubes[i])
                    {
                        // This cube was clicked.
                        Debug.Log("Hit " + cubes[i].name, cubes[i]);
                    }
                }
            }
        }
    }
}

Note: Unity also adds Debug.Log messages to the Editor and Player log files. See Log Files for more information about accessing these files on different platforms.

See Also: MonoBehaviour.print.