RxSwift - withLatestFrom combining values from both observables

Short version where your R = input.r and L = input.l

let output = input.r
.withLatestFrom(input.l) { ($0, $1) }

Just use resulting selector from your withLatestFrom. The overloaded implementation without closure simply ignores first observable. For example:

Observable.just("one")
  .withLatestFrom(Observable.just(1)) 
  { oneAsString, oneAsInt in return (oneAsString, oneAsInt) }