ToString Method

What is ToString?

ToString() is a method that all objects have, which converts objects to strings. It's used to convert numbers to strings or express object information as text.

Basic Concepts

• ToString(): Method that converts objects to strings
• Built-in: All classes inherit ToString() from Object
• Override: Can override ToString() to match your class
• Format Specifiers: Can convert numbers to desired formats

Basic Usage

Converting Numbers to Strings

using UnityEngine;

public class BasicToString : MonoBehaviour
{
    void Start()
    {
        int number = 100;
        string text = number.ToString();
        Debug.Log("Number: " + text);  // "Number: 100"
        
        float pi = 3.14f;
        string piText = pi.ToString();
        Debug.Log("Pi: " + piText);  // "Pi: 3.14"
        
        bool isTrue = true;
        string boolText = isTrue.ToString();
        Debug.Log("Boolean: " + boolText);  // "Boolean: True"
    }
}

Using with String Interpolation

using UnityEngine;

public class StringInterpolation : MonoBehaviour
{
    void Start()
    {
        int score = 1500;
        int level = 5;
        
        // Using string interpolation
        string message = $"Score: {score.ToString()}, Level: {level.ToString()}";
        Debug.Log(message);  // "Score: 1500, Level: 5"
        
        // ToString() can be omitted (automatic conversion)
        string message2 = $"Score: {score}, Level: {level}";
        Debug.Log(message2);  // "Score: 1500, Level: 5"
    }
}

Number Format Specifiers

Integer Format

using UnityEngine;

public class IntegerFormat : MonoBehaviour
{
    void Start()
    {
        int number = 12345;
        
        // Default format
        Debug.Log(number.ToString());  // "12345"
        
        // Decimal (default)
        Debug.Log(number.ToString("D"));  // "12345"
        
        // Decimal (with digit specification)
        Debug.Log(number.ToString("D8"));  // "00012345" (8 digits, padded with 0)
        
        // Hexadecimal (lowercase)
        Debug.Log(number.ToString("x"));  // "3039"
        
        // Hexadecimal (uppercase)
        Debug.Log(number.ToString("X"));  // "3039"
        
        // Hexadecimal (with digit specification)
        Debug.Log(number.ToString("X8"));  // "00003039"
    }
}

Float Format

using UnityEngine;

public class FloatFormat : MonoBehaviour
{
    void Start()
    {
        float number = 1234.5678f;
        
        // Default format
        Debug.Log(number.ToString());  // "1234.568" (rounded)
        
        // Fixed point (F)
        Debug.Log(number.ToString("F"));  // "1234.57" (2 decimal places)
        Debug.Log(number.ToString("F2"));  // "1234.57"
        Debug.Log(number.ToString("F4"));  // "1234.5678"
        
        // Exponential notation (E)
        Debug.Log(number.ToString("E"));  // "1.234568E+003"
        Debug.Log(number.ToString("e"));  // "1.234568e+003"
        
        // General format (G)
        Debug.Log(number.ToString("G"));  // "1234.568"
        
        // Number format (N) - includes thousand separators
        Debug.Log(number.ToString("N"));  // "1,234.57"
        Debug.Log(number.ToString("N2"));  // "1,234.57"
        
        // Currency format (C)
        Debug.Log(number.ToString("C"));  // "$1,235" (US locale)
        Debug.Log(number.ToString("C2"));  // "$1,234.57"
    }
}

Percent Format

using UnityEngine;

public class PercentFormat : MonoBehaviour
{
    void Start()
    {
        float ratio = 0.75f;
        
        // Percent format (P)
        Debug.Log(ratio.ToString("P"));  // "75.00 %"
        Debug.Log(ratio.ToString("P0"));  // "75 %" (no decimals)
        Debug.Log(ratio.ToString("P2"));  // "75.00 %"
    }
}

Date/Time Format

DateTime ToString

using System;
using UnityEngine;

public class DateTimeFormat : MonoBehaviour
{
    void Start()
    {
        DateTime now = DateTime.Now;
        
        // Default format
        Debug.Log(now.ToString());  // "1/15/2024 3:30:45 PM"
        
        // Short date
        Debug.Log(now.ToString("d"));  // "1/15/2024"
        
        // Long date
        Debug.Log(now.ToString("D"));  // "Monday, January 15, 2024"
        
        // Time
        Debug.Log(now.ToString("t"));  // "3:30 PM"
        Debug.Log(now.ToString("T"));  // "3:30:45 PM"
        
        // Custom format
        Debug.Log(now.ToString("yyyy-MM-dd HH:mm:ss"));  // "2024-01-15 15:30:45"
        Debug.Log(now.ToString("MM/dd/yyyy"));  // "01/15/2024"
    }
}

Overriding ToString() in Classes

Default ToString()

using UnityEngine;

public class Player
{
    public string name;
    public int level;
    public int hp;
    
    // Without overriding ToString(), only class name is returned
    // Example: "Player"
}

public class ToStringOverride : MonoBehaviour
{
    void Start()
    {
        Player player = new Player();
        player.name = "Warrior";
        player.level = 10;
        player.hp = 100;
        
        Debug.Log(player.ToString());  // "Player" (only class name)
    }
}

Overriding ToString()

using UnityEngine;

public class Player
{
    public string name;
    public int level;
    public int hp;
    
    // Override ToString()
    public override string ToString()
    {
        return $"Name: {name}, Level: {level}, HP: {hp}";
    }
}

public class ToStringOverride : MonoBehaviour
{
    void Start()
    {
        Player player = new Player();
        player.name = "Warrior";
        player.level = 10;
        player.hp = 100;
        
        Debug.Log(player.ToString());  // "Name: Warrior, Level: 10, HP: 100"
    }
}

ToString() in Unity MonoBehaviour

using UnityEngine;

public class Enemy : MonoBehaviour
{
    public string enemyName;
    public int hp;
    public int maxHp;
    
    public override string ToString()
    {
        return $"{enemyName} (HP: {hp}/{maxHp})";
    }
    
    void Start()
    {
        enemyName = "Goblin";
        hp = 50;
        maxHp = 50;
        
        Debug.Log(this.ToString());  // "Goblin (HP: 50/50)"
    }
}

Practical Usage Examples

Example 1: Score Display

using UnityEngine;
using UnityEngine.UI;

public class ScoreDisplay : MonoBehaviour
{
    public Text scoreText;
    private int score = 0;
    
    void Update()
    {
        // Convert score to string and display in UI
        scoreText.text = "Score: " + score.ToString();
        
        // Or use string interpolation
        scoreText.text = $"Score: {score}";
    }
    
    void AddScore(int points)
    {
        score += points;
    }
}

Example 2: Time Display

using System;
using UnityEngine;
using UnityEngine.UI;

public class TimeDisplay : MonoBehaviour
{
    public Text timeText;
    
    void Update()
    {
        float time = Time.time;
        
        // Convert seconds to minutes:seconds format
        int minutes = (int)(time / 60);
        int seconds = (int)(time % 60);
        
        // Use ToString("D2") to display as 2-digit number (e.g., "05:03")
        timeText.text = $"{minutes.ToString("D2")}:{seconds.ToString("D2")}";
    }
}

Example 3: Percentage Display

using UnityEngine;
using UnityEngine.UI;

public class HealthBar : MonoBehaviour
{
    public Text healthText;
    public int currentHp = 75;
    public int maxHp = 100;
    
    void Update()
    {
        float percentage = (float)currentHp / maxHp;
        
        // Display in percentage format
        healthText.text = $"Health: {percentage.ToString("P0")} ({currentHp}/{maxHp})";
        // Output: "Health: 75 % (75/100)"
    }
}

Example 4: Currency Display

using UnityEngine;
using UnityEngine.UI;

public class CurrencyDisplay : MonoBehaviour
{
    public Text goldText;
    private int gold = 1234567;
    
    void Update()
    {
        // Display in currency format (with thousand separators)
        goldText.text = "Gold: " + gold.ToString("N0");
        // Output: "Gold: 1,234,567"
        
        // Or with currency symbol
        goldText.text = gold.ToString("C0");
        // Output: "$1,234,567"
    }
}

Example 5: Debug Information Output

using UnityEngine;

public class DebugInfo : MonoBehaviour
{
    public Vector3 position;
    public float speed;
    public bool isMoving;
    
    public override string ToString()
    {
        return $"Position: {position}, Speed: {speed.ToString("F2")}, Moving: {isMoving}";
    }
    
    void Update()
    {
        // Output debug information
        Debug.Log(this.ToString());
        // Output: "Position: (1, 2, 3), Speed: 5.50, Moving: True"
    }
}

Format Specifier Summary

Number Formats

Format	Description	Example
D or d	Decimal	123.ToString("D") → "123"
D5	Decimal (5 digits)	123.ToString("D5") → "00123"
X	Hexadecimal (uppercase)	255.ToString("X") → "FF"
x	Hexadecimal (lowercase)	255.ToString("x") → "ff"
F or f	Fixed point	3.14.ToString("F2") → "3.14"
E or e	Exponential notation	1234.ToString("E") → "1.234000E+003"
N or n	Number format (thousand separators)	1234.ToString("N") → "1,234.00"
C or c	Currency format	1234.ToString("C") → "$1,234"
P or p	Percent	0.75.ToString("P") → "75.00 %"

Date Formats

Format	Description	Example
d	Short date	DateTime.Now.ToString("d") → "1/15/2024"
D	Long date	DateTime.Now.ToString("D") → "Monday, January 15, 2024"
t	Short time	DateTime.Now.ToString("t") → "3:30 PM"
T	Long time	DateTime.Now.ToString("T") → "3:30:45 PM"
yyyy-MM-dd	Custom format	DateTime.Now.ToString("yyyy-MM-dd") → "2024-01-15"

Notes

1. Null Handling: Calling ToString() on null object throws NullReferenceException
2. Performance: String interpolation ($"...") automatically calls ToString(), so it's convenient
3. Locale: Currency (C) or date formats may vary depending on system locale
4. Override: Overriding ToString() to match your class is useful for debugging

Practical Tips

Tip 1: Using with Null Check

using UnityEngine;

public class NullSafeToString : MonoBehaviour
{
    void Start()
    {
        object obj = null;
        
        // Safe ToString() call
        string result = obj?.ToString() ?? "null";
        Debug.Log(result);  // "null"
        
        // Or
        if (obj != null)
        {
            Debug.Log(obj.ToString());
        }
    }
}

Tip 2: Combining Multiple Values

using UnityEngine;

public class CombineValues : MonoBehaviour
{
    void Start()
    {
        int score = 1500;
        int level = 5;
        float time = 123.45f;
        
        // Combine multiple values into string
        string info = $"Score: {score.ToString("N0")}, Level: {level}, Time: {time.ToString("F2")}s";
        Debug.Log(info);
        // Output: "Score: 1,500, Level: 5, Time: 123.45s"
    }
}

Tip 3: Conditional Format

using UnityEngine;

public class ConditionalFormat : MonoBehaviour
{
    void Start()
    {
        float number = 1234.567f;
        
        // Show decimals if present, otherwise show as integer
        string formatted = number % 1 == 0 
            ? number.ToString("N0") 
            : number.ToString("F2");
        
        Debug.Log(formatted);
    }
}

Tip 4: Outputting List Elements

using System.Collections.Generic;
using UnityEngine;

public class ListToString : MonoBehaviour
{
    void Start()
    {
        List<int> numbers = new List<int> { 1, 2, 3, 4, 5 };
        
        // Convert each list element to string
        string result = string.Join(", ", numbers.ConvertAll(x => x.ToString()));
        Debug.Log(result);  // "1, 2, 3, 4, 5"
        
        // Or using LINQ
        // string result = string.Join(", ", numbers.Select(x => x.ToString()));
    }
}

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