Function fmty::concat_map_once
source · pub fn concat_map_once<I, R, F>(iter: I, f: F) -> ConcatMapOnce<I::IntoIter, F>where
I: IntoIterator,
F: Fn(I::Item) -> R,
Expand description
Concatenates mapped Iterator
results, at most once.
This is a non-Clone
alternative to concat_map()
. It uses interior
mutability to take ownership of the iterator in the first call to
Display::fmt()
. As a result, ConcatMapOnce
does not implement
Sync
.
Examples
let value = fmty::concat_map_once(["hola", "mundo"], fmty::to_ascii_uppercase);
assert_eq!(value.to_string(), "HOLAMUNDO");
assert_eq!(value.to_string(), "");