public/subjects/unwrap_or_expect/README.md

unwrap

Instructions

It will be given a function called odd_to_even, that returns an Result. If its an error it will return a tuple with a string, indicating the error, and a vector with the elements that justifies the error

The objective is to execute the odd_to_even function and handle the error given by it

Create the following functions that receives a vector :

• expect that returns the error adding the sting "ERROR "
• unwrap_or that in case of error returns an empty vector
• unwrap_err that returns error if its Ok and returns the string containing the error in case of Err
• unwrap that unwraps the Result
• unwrap_or_else that in case of error returns a the vector that justifies the error

Expected Function

pub fn odd_to_even(data: Vec<u32>) -> Result<Vec<u32>, (String, Vec<u32>)> {}
pub fn expect(v: Vec<u32>) -> Vec<u32> {}
pub fn unwrap_or(v: Vec<u32>) -> Vec<u32> {}
pub fn unwrap_err(v: Vec<u32>) -> (String, Vec<u32>) {}
pub fn unwrap(v: Vec<u32>) -> Vec<u32> {}
pub fn unwrap_or_else(v: Vec<u32>) -> Vec<u32> {}

Usage

Here is a program to test your function

fn main() {
    // this will give an expect error
    // println!("{:?}", expect(vec![1, 3, 2, 5]));
    println!("{:?}", unwrap_or(vec![1, 3, 2, 5]));
    println!("{:?}", unwrap_or(vec![1, 3, 5]));
    println!("{:?}", unwrap_err(vec![1, 3, 2, 5]));
    // this will give an error that is unwraped
    // println!("{:?}", unwrap_err(vec![1, 3, 5]));
    println!("{:?}", unwrap(vec![1, 3, 5]));
    // this will give an error
    // println!("{:?}", unwrap(vec![1, 3, 2, 5]));
    println!("{:?}", unwrap_or_else(vec![1, 3, 5]));
    println!("{:?}", unwrap_or_else(vec![3, 2, 6, 5]));
}

And its output:

student@ubuntu:~/[[ROOT]]/test$ cargo run
[]
[2, 4, 6]
("There is a even value in the vector!", [2])
[2, 4, 6]
[2, 4, 6]
[2, 6]
student@ubuntu:~/[[ROOT]]/test$

Notions

• https://doc.rust-lang.org/std/?search=unwrap