pub fn std_deviation(data: &[usize]) -> Option<f64> { ... }
pub struct CompanyEval { pub final_value: usize, } let c_e: Vec<CompanyEval>;
let a: Vec<usize> = c_e.iter().map(|m| -> usize {m.final_value}).collect(); let value_stdev = crate::utils::std_deviation(&a).unwrap();



한 줄에 쓰면

a value of type `[usize]` cannot be built from an iterator over elements of type `usize`

the trait `FromIterator<usize>` is not implemented for `[usize]` (lsp)



라고 나옴...