Two quick iterator questions

[miehe-dup]

Hi! I have a struct Zone and this initialization:

let zs: Vec<_> = [0;4].iter().map(|_| Zone::default()).collect();
println!("{:?}", zs);

Then, there is struct Block with impl Into<Block> for Zone:

let bs: Vec<Block> = zs.into_iter().map(|x| x.into()).collect();
println!("{:?}", bs);

Both feel unnecessary wordy to me. Please help me improve!

[farnbams]

Depending on Zone and Block you have various options.

If Zone is Copy Clone (sry remembered this wrong) you could simply write:

let zs = [Zone::default(); 4].to_vec();

But I think thats not the case. In order to remove one call you could use a Range:

let zs: Vec<_> = (0..4).map(|_| Zone::default()).collect();

For the Block creation you can do what clippy recommends:

let bs: Vec<Block> = zs.into_iter().map(Zone::into).collect();

For the rest I see no sensible reason to remove.

---

One note: Often it is more ergonomic to implement From rather than Into. First because From automaticly implements Into and second then you could write:

bs: Vec<_> = zs.into_iter().map(Block::from).collect();

But thats just a matter of personal taste.

[spunit262]

If Zone is Clone

let zs = vec![Zone::default(); 4];

otherwise

let zs: Vec<_> = std::iter::repeat_with(Zone::default).take(4).collect();

For the second I can only repeat the From recommendation.