CodeBlanks Logo Icon CodeBlanks
Login Register

match basics

Match a value against patterns with match.

match basics

match compares a value against patterns in order and runs the first arm that matches. Arms are written pattern => expression; patterns can be literals, ranges (1..=5), several values (1 | 2) or _:

let gun = 6;
let tur = match gun {
    1..=5 => "iş günü",
    6 | 7 => "hafta sonu",
    _ => "geçersiz",
};
println!("{tur}");

A match must be exhaustive: every possible value must be covered by an arm.

Arm bodies

If an arm runs several lines, curly braces are used; its last expression is the arm's value:

match komut {
    "ekle" => {
        sayac += 1;
        println!("eklendi");
    }
    "sil" => sayac -= 1,
    _ => println!("bilinmeyen: {komut}"),
}

Arm order matters: _ goes last, otherwise later arms are never reached and the compiler warns.

Practice Kind of day

Write fn gun_turu(g: u8) -> &'static str: 1–5 "iş günü", 6 and 7 "hafta sonu", otherwise "geçersiz". Print the results for 3, 7 and 9 on separate lines.

Starter code

main.rs
fn main() {
    // buraya yaz
}

Sample solution

main.rs
fn gun_turu(g: u8) -> &'static str {
    match g {
        1..=5 => "iş günü",
        6 | 7 => "hafta sonu",
        _ => "geçersiz",
    }
}

fn main() {
    for g in [3, 7, 9] {
        println!("{}", gun_turu(g));
    }
}

Expected output

iş günü
hafta sonu
geçersiz

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Why is <code>match</code> safer than a switch?

  • The compiler checks that every case is handled Correct answer
  • It's faster
  • It requires break
  • It only works with numbers

Explanation: A missing case is a compile error; also arms don't fall through.

2 Several values

Question 
match gun {
    6 ____ 7 => "hafta sonu",
    _ => "iş günü",
}
Answer 
match gun {
    6 | 7 => "hafta sonu",
    _ => "iş günü",
}

Explanation: | combines several patterns in one arm.

3 Pattern and meaning

Term Meaning
3 A single value
1..=5 Inclusive range
6 | 7 Several values
_ Everything else

All lessons in Beginner

1 Rust basics

  1. What is Rust?
  2. Project with Cargo
  3. Your first program
  4. println! and formatting
  5. Comments
  6. Summary - Rust basics

2 Variables

  1. Variables with let
  2. Mutability with mut
  3. Constants with const
  4. Static variables
  5. Shadowing
  6. Summary - Variables

3 Data types

  1. Integers
  2. Floating point
  3. Bool and char
  4. Tuple
  5. Array
  6. Summary - Data types

4 Strings

  1. &str vs String
  2. Creating a String
  3. Concatenating strings
  4. format! macro
  5. String length
  6. Summary - Strings

5 Project: Calculator

  1. Project skeleton
  2. Reading input
  3. Computing
  4. Error handling
  5. Loop and exit

6 Functions

  1. Defining with fn
  2. Parameters
  3. Return value
  4. Expressions and statements
  5. Early return
  6. Summary - Functions

7 Control flow

  1. if-else
  2. match basics
  3. loop
  4. while loop
  5. for loop
  6. Summary - Control flow

8 Ownership

  1. What is ownership?
  2. Move semantics
  3. Copy trait
  4. Functions and ownership
  5. Return and ownership
  6. Summary - Ownership

9 Borrowing

  1. References
  2. Mutable reference
  3. Borrowing rules
  4. Dangling reference
  5. References and functions
  6. Summary - Borrowing

10 Slices

  1. String slices
  2. Slice syntax
  3. Array slices
  4. Slices and functions
  5. Range types
  6. Summary - Slices

11 Project: Guessing game

  1. Game skeleton
  2. Reading input
  3. Comparing numbers
  4. Random number
  5. Loop and exit

12 Structs

  1. Struct definition
  2. Creating an instance
  3. Tuple struct
  4. Unit-like struct
  5. Field update
  6. Summary - Structs

13 Methods

  1. impl block
  2. self parameter
  3. &mut self
  4. Associated functions
  5. Multiple impl blocks
  6. Summary - Methods

14 Enums

  1. Enum definition
  2. Variants
  3. Variants with data
  4. Option<T>
  5. Option instead of null
  6. Summary - Enums

15 Pattern matching

  1. match patterns
  2. Value binding
  3. if let
  4. while let
  5. _ wildcard
  6. Summary - Pattern matching

16 Project: To-do CLI

  1. Task model
  2. Adding
  3. Listing
  4. Marking done
  5. Reading commands

17 Vectors

  1. Vec<T>
  2. Push and pop
  3. Index and get
  4. Looping a vector
  5. with_capacity
  6. Summary - Vectors

18 Advanced strings

  1. String and &str conversion
  2. chars and bytes
  3. Slicing strings
  4. contains and replace
  5. split and join
  6. Summary - Advanced strings

19 Error handling

  1. Result<T, E>
  2. panic!
  3. ? operator
  4. match and Result
  5. unwrap and expect
  6. Summary - Error handling

20 Beginner final

  1. Vowel counter
  2. Average calculator
  3. Bank account
  4. Temperature converter