pub fn unfold<F, S, A>(value: S, f: F) -> impl Iterator<Item = A>
Expand description
Create an iterator of values using a function to update an owned state value.
The function is called with the current state as its argument, and should
return an Option
of a tuple of the next value to
yield from the iterator and the updated state. If the function returns
None
, the iterator ends.
§Examples
// Create an infinite stream of numbers, starting at 0.
let mut it = unfold(0, |i| Some((i, i + 1)));
// Make a list out of its first five elements.
let numbers = Vector::from_iter(it.take(5));
assert_eq!(numbers, vector![0, 1, 2, 3, 4]);