How can I get a String joined from references of Strings that I cannot move since these references get used elsewhere?
let features: Vec<&String>
let my_str: String = features.iter().copied().into_iter().collect::<Vec<String>>().join(",");
value of type
Vec<std::string::String>cannot be built from `std::iter::Iterator<Item=&std::string::String>
I know I can solve this by map(|f| format!("{f}")) before collecting, but that seems overkill.
You can clone each string by inserting .cloned() after .copied(). But that's unnecessary: you can just convert to a vector of &str and join those. The .into_iter() is also unnecessary.
See e.g.: Playground
I think you really want
features.iter().map(|s| s.as_str()).intersperse(",").collect()
but that's going to be noisy or unergonomic if you're not on nightly.
Edit: See 
@steffahn sadly no join method is found in that case:
method not found in
std::slice::Iter<'_, &std::string::String>
This however does work, though probably not efficient?:
features.iter().map(|s| s.to_string()).collect();
That's not the standard method, you have to use itertools::Itertools.
noice!
And I guess this takes the cake as most performance as well as explained here:
Often, the Rust optimiser will be able to figure out that a clone can be replaced with a faster copy. However, this isn't guaranteed, so use
copied()where you can, to make sure you end up with the fastest binary.
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