[rtoway]

In Rust, many times this kind of code will compile to the same code using plain old loops and if statements

[mastax]

Yes, however for this specific situation `replace()` is not an iterator adapter but a method of `str` which returns a newly allocated `String`. In practice, the compiler does not do something smarter than that: https://rust.godbolt.org/z/z573Mvjzz

[rtoway]

Ah you are right about that. Yes, it would be a nice place to avoid an allocation