What are Tuples?

  • Tuples are heterogeneous sequences of elements, meaning, each element in a tuple can have a different data type. Just like arrays, tuples are of a fixed length.

  • Define a Tuple

A tuple can be defined by writing let followed by the name of the tuple and then enclosing the values within the parenthesis.

  • Syntax 1
    • The syntax below defines a tuple without specifying the type. However, the compiler can infer the type.

  • Syntax 2
    • The syntax below defines a tuple by specifying the type.

Example

The following illustration explains the concept:

#[allow(unused_variables, unused_mut)]
fn main() {
    //define a tuple
    let person_data = ("Alex", 48, "35kg", "6ft");
    // define a tuple with type annotated
    let person_data : (&str, i32, &str, &str) = ("Alex", 48, "35kg", "6ft");
}
  • Access the Value of the Tuple
  • Unlike array which uses [] for accessing an element, the value of the tuple can be accessed using the dot operator (.).
tuplename.indexvalue

To get the individual values out of a tuple, we can use pattern matching to destructure a tuple value, like this:

let person_data = ("Alex", 48, "35kg", "6ft");
 let (w, x, y, z) = person_data;
fn main() {
   //define a tuple
   let person_data = ("Alex", 48, "35kg", "6ft");
   // access value of a tuple
   println!("The value of the tuple at index 0 and index 1 are {} {}",person_data.0,person_data.1);

   //define a tuple
   let person_data = ("Alex", 48, "35kg", "6ft");
   // get individual values out of tuple
   let (w ,x, y, z) = person_data;
   //print values
   println!("Name : {}",w);
   println!("Age : {}",x);
   println!("Weight : {}",y);
   println!("Height : {}",z);
}

output:-

The value of the tuple at index 0 and index 1 are Alex 48
Name : Alex
Age : 48
Weight : 35kg
Height : 6ft

How to Make a Tuple Mutable?

Just like a variable becomes mutable by adding the mut keyword after let, the same goes for a tuple.

fn main() {
    //define a tuple
    let mut person_data = ("Alex", 48, "35kg", "6ft");
    //print the value of tuple
    println!("The value of the tuple at index 0 and index 1 are {} {}", person_data.0, person_data.1);
    //modify the value at index 0
    person_data.0 = "John";
    //print the modified value
    println!("The value of the tuple at index 0 and index 1 are {} {}", person_data.0, person_data.1);
}

output:-

The value of the tuple at index 0 and index 1 are Alex 48
The value of the tuple at index 0 and index 1 are John 48

Print the Tuple

The whole tuple can be traversed using the debug trait.

fn main() {
    //define a tuple
    let person_data = ("Alex", 48, "35kg", "6ft");
    //print the value of tuple
    println!("Tuple - Person Data : {:?}",person_data);
}

output:-

Tuple - Person Data : ("Alex", 48, "35kg", "6ft")

Quiz

Test your understanding of tuples in Rust!

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