I'm trying to display the minimum value within a vector in Rust and can't find a good way to do so.
Given a vector of i32 :
let mut v = vec![5, 6, 8, 4, 2, 7];
My goal here is to get the minimum value of that vector without having to sort it.
What is the best way to get the minimum value within a Vec<i32> in Rust ?
let minValue = vec.iter().min();
match minValue {
Some(min) => println!( "Min value: {}", min ),
None => println!( "Vector is empty" ),
}
https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.min
fn min(self) -> Option<Self::Item> where Self::Item: Ord,Returns the minimum element of an iterator.
If several elements are equally minimum, the first element is returned. If the iterator is empty, None is returned.
I found this Gist which has some common C#/.NET Linq operations expressed in Swift and Rust, which is handy: https://gist.github.com/leonardo-m/6e9315a57fe9caa893472c2935e9d589
Some(8) when I actually need to get only 8when I do a println!("{:#?}", maxValue); since println!("{}", maxValue); returns an error.
println!("{}", maxValue.unwrap());
iter.copied().min() gets significantly better codegen, it even auto vectorizes well. If you doing without copied() it is... a mess (copied() at the end doesn't help).let mut v = vec![5, 6, 8, 4, 2, 7];
let minValue = *v.iter().min().unwrap();
iter.copied().min() gets significantly better codegen, it even auto vectorizes well. If you doing without copied() it is... a mess (copied() at the end doesn't help).Hi @octano As Dai has already answered, min/max return Option<> value, so you can only match it as in example:
fn main() {
let vec_to_check = vec![5, 6, 8, 4, 2, 7];
let min_value = vec_to_check.iter().min();
match min_value {
None => println!("Min value was not found"),
Some(i) => println!("Min Value = {}", i)
}
}
match part. This was just bad timing.
iter.copied().min() gets significantly better codegen, it even auto vectorizes well. If you doing without copied() it is... a mess (copied() at the end doesn't help).let max = nums.iter().max().unwrap_or(&0);
You can use unwrap_or(value) to return default value if max not found.
.copied().unwrap_or(0).iter.copied().min() gets significantly better codegen, it even auto vectorizes well. If you doing without copied() it is... a mess (copied() at the end doesn't help).See the functions: fn min() and fn fold().
Another option, not necessarily the most efficient.
"Folding is useful whenever you have a collection of something, and want to produce a single value from it."
fn main() {
let values: Vec<i32> = vec![5, 6, 8, 4, 2, 7];
// The empty vector must be filtered beforehand!
// let values: Vec<i32> = vec![]; // Not work!!!
// Get the minimum value without being wrapped by Option<T>
let min_value: i32 = values
.iter()
//.into_iter()
//.fold(i32::MAX, i32::min);
.fold(i32::MAX, |arg0: i32, other: &i32| i32::min(arg0, *other));
println!("values: {values:?}");
println!("min_value: {min_value}");
assert_eq!(min_value, 2);
}
See Rust Playground
Iterator::min().