Iterating over Results
An Iter::map operation might fail, for example:
Let's step through strategies for handling this.
Ignore the failed items with filter_map()
filter_map calls a function and filters out the results that are None.
Fail the entire operation with collect()
Result implements FromIter so that a vector of results (Vec<Result<T, E>>)
can be turned into a result with a vector (Result<Vec<T>, E>). Once an
Result::Err is found, the iteration will terminate.
This same technique can be used with Option.
Collect all valid values and failures with partition()
When you look at the results, you'll note that everything is still wrapped in
Result. A little more boilerplate is needed for this.