Deconstruction
Unpack tuples into separate variables.
Deconstruction is a free C# Academy lesson on CoddyKit. This is lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C# Academy learning path, and your progress syncs across the web and the CoddyKit app. The C# Academy course includes 4 lessons in total.
What Is Deconstruction?
Deconstruction splits a tuple (or object) into separate variables in one statement, so you can name each part directly.
using System;
class Program
{
static void Main()
{
var point = (3, 4);
(int x, int y) = point;
Console.WriteLine("x=" + x + ", y=" + y);
}
}Deconstructing a Tuple
Put the target variables in parentheses on the left of =. Each receives the matching tuple element.
using System;
class Program
{
static void Main()
{
var user = ("Ada", 36);
(string name, int age) = user;
Console.WriteLine(name + " is " + age);
}
}Using var in Deconstruction
You can let the compiler infer types with var, either per variable or for the whole group.
using System;
class Program
{
static void Main()
{
var data = (1, "one", true);
var (id, word, flag) = data;
Console.WriteLine(id + " " + word + " " + flag);
}
}Deconstructing a Method Result
You can deconstruct the tuple a method returns directly into named variables.
using System;
class Program
{
static (int, int) MinMax(int a, int b) => a < b ? (a, b) : (b, a);
static void Main()
{
var (lo, hi) = MinMax(8, 3);
Console.WriteLine("min=" + lo + ", max=" + hi);
}
}Discarding Values
Use an underscore _ to ignore parts you do not need during deconstruction.
using System;
class Program
{
static (int, int, int) Rgb() => (255, 128, 0);
static void Main()
{
var (r, _, _) = Rgb();
Console.WriteLine("Red channel: " + r);
}
}Deconstructing into Existing Variables
You can assign to already-declared variables by leaving out the type names.
using System;
class Program
{
static void Main()
{
int a = 0, b = 0;
(a, b) = (10, 20);
Console.WriteLine(a + ", " + b);
}
}Swapping with Tuples
A neat trick: swap two variables in one line using tuple deconstruction, no temp variable needed.
using System;
class Program
{
static void Main()
{
int x = 1, y = 2;
(x, y) = (y, x);
Console.WriteLine("x=" + x + ", y=" + y);
}
}The Deconstruct Method
Your own classes can support deconstruction by defining a Deconstruct method with out parameters.
using System;
class Point
{
public int X, Y;
public Point(int x, int y) { X = x; Y = y; }
public void Deconstruct(out int x, out int y)
{
x = X;
y = Y;
}
}
class Program
{
static void Main()
{
var p = new Point(5, 9);
var (px, py) = p;
Console.WriteLine(px + ", " + py);
}
}Multiple Deconstruct Overloads
A class can offer several Deconstruct overloads exposing different numbers of values.
using System;
class Person
{
public string Name; public int Age; public string City;
public Person(string n, int a, string c) { Name = n; Age = a; City = c; }
public void Deconstruct(out string name, out int age)
{
name = Name; age = Age;
}
}
class Program
{
static void Main()
{
var p = new Person("Ada", 36, "London");
var (name, age) = p;
Console.WriteLine(name + ", " + age);
}
}Deconstruction in foreach
When looping over a collection of tuples, you can deconstruct each element right in the foreach header.
using System;
using System.Collections.Generic;
class Program
{
static void Main()
{
var pairs = new List<(string, int)>
{
("Ann", 30),
("Bob", 25)
};
foreach (var (name, age) in pairs)
Console.WriteLine(name + " is " + age);
}
}Putting It Together
Deconstruction makes code that returns or stores multiple values read cleanly, naming each part at the point of use.
using System;
class Program
{
static (int Quotient, int Remainder) Divide(int a, int b) => (a / b, a % b);
static void Main()
{
var (q, r) = Divide(17, 5);
Console.WriteLine("17 / 5 = " + q + " remainder " + r);
}
}Quick Check
Test your understanding of deconstruction.
Recap
Deconstruction splits a tuple or object into named variables in one statement. Use var (a, b) = ..., discard parts with _, swap variables, and deconstruct in foreach. Custom classes opt in with a Deconstruct method using out parameters, optionally overloaded.
using System;
class Program
{
static void Main()
{
var (a, b, c) = (1, 2, 3);
Console.WriteLine(a + b + c);
}
}
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Frequently Asked Questions
Is the “Deconstruction” lesson free?
Yes — the full text of “Deconstruction” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C# Academy course, upgrade to CoddyKit PRO. The C# Academy course includes 4 lessons in total.
What will I learn in “Deconstruction”?
Unpack tuples into separate variables. You practise C# Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start C# Academy?
No prior experience is required. C# Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 4.
How long does the “Deconstruction” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this C# Academy lesson?
Yes. Every C# Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.