Understanding when to use String vs str

[scottmcm]

@plantpowerjames

but is that a good general rule of thumb?

Reusing a related post I wrote a while ago:

Returning strings: `String` vs. `&str`

Here's my Rust 101 rules for this: "&str for parameters; String for return types". This always works, and has no borrowck complications, but is sometimes inefficient. the small tweak to add "If you always need to to_owned/to_string the &str parameter, change it to a String parameter". That's more efficient when your caller happens to already have a String, no less efficient if they don't, and still doesn't require thinking about lifetimes. if you're always returning a substring of on…

And yes, until you're comfortable with everything else, don't try to store &strs in structs.

I'll also link my favourite article about String vs str in Rust:

https://chrismorgan.info/blog/rust-fizzbuzz/

(It looks like a FizzBuzz article, but it's actually about strings.)