Assumption -- The Vec<f32>
does not have any NaN
values or exhibit any NaN
behavior.
Take the following sample set:
0.28
0.3102
0.9856
0.3679
0.3697
0.46
0.4311
0.9781
0.9891
0.5052
0.9173
0.932
0.8365
0.5822
0.9981
0.9977
What is the neatest and most stable way to get the index of the highest value in the above list (values can be negative)?
My initial attempts were along the following lines:
let _tmp = *nets.iter().max_by(|i, j| i.partial_cmp(j).unwrap()).unwrap();
let _i = nets.iter().position(|&element| element == _tmp).unwrap();
Where nets
is a &Vec<f32>
. Which to me seems blatantly incorrect.
The Python equivalent of this that works (taking into consideration the above assumption):
_i = nets.index(max(nets))
I will probably do something like this:
fn main() -> Result<(), Box<std::error::Error>> {
let samples = vec![
0.28, 0.3102, 0.9856, 0.3679, 0.3697, 0.46, 0.4311, 0.9781, 0.9891, 0.5052, 0.9173, 0.932,
0.8365, 0.5822, 0.9981, 0.9977,
];
// Use enumerate to get the index
let mut iter = samples.iter().enumerate();
// we get the first entry
let init = iter.next().ok_or("Need at least one input")?;
// we process the rest
let result = iter.try_fold(init, |acc, x| {
// return None if x is NaN
let cmp = x.1.partial_cmp(acc.1)?;
// if x is greater the acc
let max = if let std::cmp::Ordering::Greater = cmp {
x
} else {
acc
};
Some(max)
});
println!("{:?}", result);
Ok(())
}
This could be implemented by adding a trait on Iterator with for example the function try_max_by
.