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// Tuples can be used as function arguments and as return values
fn reverse(pair: (i32, bool)) -> (bool, i32) {
// `let` can be used to bind the members of a tuple to variables
let (integer, boolean) = pair;
(boolean, integer)
}
// The following struct is for the activity.
#[derive(Debug)]
struct Matrix(f32, f32, f32, f32);
fn main() {
// A tuple with a bunch of different types
let long_tuple = (1u8, 2u16, 3u32, 4u64,
-1i8, -2i16, -3i32, -4i64,
0.1f32, 0.2f64,
'a', true);
// Values can be extracted from the tuple using tuple indexing
println!("long tuple first value: {}", long_tuple.0);
println!("long tuple second value: {}", long_tuple.1);
// Tuples can be tuple members
let tuple_of_tuples = ((1u8, 2u16, 2u32), (4u64, -1i8), -2i16);
// Tuples are printable
println!("tuple of tuples: {:?}", tuple_of_tuples);
// But long Tuples cannot be printed
// let too_long_tuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13);
// println!("too long tuple: {:?}", too_long_tuple);
// TODO ^ Uncomment the above 2 lines to see the compiler error
let pair = (1, true);
println!("pair is {:?}", pair);
println!("the reversed pair is {:?}", reverse(pair));
// To create one element tuples, the comma is required to tell them apart
// from a literal surrounded by parentheses
println!("one element tuple: {:?}", (5u32,));
println!("just an integer: {:?}", (5u32));
//tuples can be destructured to create bindings
let tuple = (1, "hello", 4.5, true);
let (a, b, c, d) = tuple;
println!("{:?}, {:?}, {:?}, {:?}", a, b, c, d);
let matrix = Matrix(1.1, 1.2, 2.1, 2.2);
println!("{:?}", matrix);
}
Tuples in rust
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//EXAMPLE 1
// returns a tuple: with the original value & the exponential function of the value. and the natural logarithm of the absolute value.
pub fn nbr_function(c: i32) -> (i32, f64, f64) {
return (c, (c as f64).exp(), (c.abs() as f64).ln())
}
// returns a tuple: with the original value & the exponential function of each value as a string (see the example).
pub fn str_function(a: String) -> (String, String) {
// Split by whitespace.
let number_strs = a.split_whitespace();
// Create a string to return.
let mut result_string: String = String::new();
for num_str in number_strs {
// Get exponential.
let num = num_str.parse::<f64>().unwrap().exp();
result_string.push_str(&(num.to_string()));
result_string.push(' ');
}
// Get rid of last char
result_string.truncate(result_string.len() - 1);
(a, result_string)
}
// returns a tuple: with the original value & the natural log of each absolute value.
pub fn vec_function(numbers: Vec<i32>) -> (Vec<i32>, Vec<f64>) {
let mut result_vector: Vec<f64> = Vec::new();
// loop through each value in the input array
for num in numbers.clone() {
// for each element, calculate the natural log of the absolute value and then push it to the new vector.
result_vector.push((num.abs() as f64).ln())
}
(numbers, result_vector)
}
// EXAMPLE 2
#[derive(Debug, PartialEq, Eq)]
pub struct Student(pub u32, pub String, pub String);
pub fn id(student: &Student) -> u32 {
student.0
}
pub fn first_name(student: &Student) -> String {
student.1.clone()
}
pub fn last_name(student: &Student) -> String {
student.2.clone()