Expand description
Fallible lookup, the operation the unordered field types diff through.
std::ops::Index cannot express a diff: it panics when the element is
absent, and “is this element on the other side?” is the only question a
membership diff asks. TryIndex is that trait with the answer made
fallible, which is what lets bag and map
push the lookup down into the collection instead of scanning it.
The consequence is that a field’s cost is the cost of the collection you
picked: a diff over a HashSet or HashMap is O(n), and over a
BTreeSet or BTreeMap it is O(n log n).
Traits§
- TryIndex
- A collection that can look an element up by key without panicking when it is not there.
- TryIndex
Mut - A
TryIndexwhose elements can also be modified in place.