Variables and serialization in Unity - Step-by-Step Execution

Concept Flow - Variables and serialization

Declare variable

↓

Assign value

↓

Serialize variable

↓

Save to file or memory

↓

Deserialize variable

↓

Use restored value

↓

End

This flow shows how a variable is declared, given a value, saved (serialized), then loaded back (deserialized) for use.

Execution Sample

Unity

using UnityEngine;

public class Example : MonoBehaviour {
    [SerializeField] private int score = 10;
}

This code declares a private variable 'score' with initial value 10 and marks it to be serialized by Unity.

Execution Table

Step	Action	Variable	Value	Serialization State
1	Declare variable 'score'	score	undefined	Not serialized yet
2	Assign initial value	score	10	Not serialized yet
3	Serialize variable	score	10	Serialized to Unity Editor and saved
4	Save to file/memory	score	10	Stored in scene or prefab data
5	Deserialize variable	score	10	Loaded back from saved data
6	Use variable in game	score	10	Active in runtime
7	End	-	-	-

💡 Serialization completes when variable is saved and loaded back correctly.

Variable Tracker

Variable	Start	After Assign	After Serialize	After Deserialize	Final
score	undefined	10	10	10	10

Key Moments - 3 Insights

Why do we use [SerializeField] on a private variable?

Because private variables are hidden from Unity's Inspector by default, [SerializeField] tells Unity to save and show it anyway, as shown in step 3 of the execution_table.

Does serialization change the variable's value?

No, serialization saves the current value without changing it. The value remains 10 before and after serialization (see variable_tracker).

What happens if we don't serialize a variable?

Unity won't save its value between sessions, so it resets to default or code value on reload. This is why serialization is important (step 3 and 5).

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'score' after step 2?

A 0

B undefined

C 10

D null

💡 Hint

Check the 'Value' column at step 2 in the execution_table.

At which step does the variable 'score' get saved to file or memory?

A Step 3

B Step 4

C Step 5

D Step 6

💡 Hint

Look for the action mentioning saving to file or memory in the execution_table.

If we remove [SerializeField], what happens to the variable 'score' in Unity Inspector?

A It becomes invisible and not serialized

B It causes a compile error

C It remains visible and serialized

D It becomes public automatically

💡 Hint

Refer to the key_moments about [SerializeField] usage.

Concept Snapshot

Variables hold data in Unity scripts.
[SerializeField] makes private variables visible and saved.
Serialization saves variable values to disk or memory.
Deserialization restores saved values when loading.
Without serialization, values reset on reload.

Full Transcript

This lesson shows how variables in Unity scripts can be saved and loaded using serialization. We start by declaring a variable called 'score' and assign it the value 10. Using the [SerializeField] attribute, Unity knows to save this private variable's value. Serialization means saving the variable's current value to a file or memory so it can be restored later. When the game or editor reloads, Unity deserializes the variable, loading back the saved value. This way, the variable keeps its value between sessions. Without serialization, private variables would reset to default values and not keep changes made in the editor or during gameplay. The execution table traces each step from declaration, assignment, serialization, saving, deserialization, to usage. The variable tracker shows the value stays 10 throughout. Key moments clarify why [SerializeField] is needed and that serialization does not change the value. The quiz tests understanding of variable values at steps and the effect of serialization attributes.