Return local String as a slice (&str)

Question

There are several questions that seem to be about the same problem I\'m having. For example see here and here. Basically I\'m trying to build a String in a loca

Answer 1

In certain cases, you are passed a string slice and may conditionally want to create a new string. In these cases, you can return a Cow. This allows for the reference when possible and an owned String otherwise:

use std::borrow::Cow;

fn return_str<'a>(name: &'a str) -> Cow<'a, str> {
    if name.is_empty() {
        let name = "ACTG".repeat(10);
        name.into()
    } else {
        name.into()
    }
}