find the variance of a list of numbers in rust

To find the variance of a list of numbers in Rust, we need to implement the following steps:

1. Calculate the mean of the list of numbers.
2. Calculate the sum of the squares of the differences between each number and the mean.
3. Divide the result of step 2 by the number of elements in the list minus one.

Here's the Rust code to implement the variance calculation:

main.rs
use std::f64;

fn main() {
    let nums = vec![1.0, 2.0, 3.0, 4.0, 5.0];
    let mean = nums.iter().sum::<f64>() / nums.len() as f64;
    let variance = nums.iter().map(|num| (num - mean).powi(2)).sum::<f64>() / (nums.len() - 1) as f64;
    println!("The variance of the list of numbers is: {}", variance);
}
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In this code snippet, we first define a nums vector that contains the list of numbers. We then calculate the mean of nums by dividing the sum of its elements by its length.

Next, we calculate the variance of nums by iterating over its elements using the map method, which applies a closure that calculates the square of the difference between each number and the mean. We then sum the squared differences and divide the total by the number of elements in the list minus one.

Finally, we print the resulting variance. This code should output:

main.rs
The variance of the list of numbers is: 2.5
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