Re: My first program: sublime (reverse of "extract" function)
- Posted by jimcbrown (admin) May 19, 2013
- 2407 views
Why can't you keep a copy of the original list? What type of processing are you doing that makes this solution unsuitable?
That's slightly less trivial code:
sequence InputData = {0.01, 0.05, 0.08, 0.03, 0.02} sequence OutputData = sort(InputData) sequence OriginalOrder = sublime(InputData, OutputData) for i = 2 to length(OutputData) do OutputData[i] *= 1 - OutputData[i-1] end for OutputData = extract(OutputData, OriginalOrder)
I think I get it. Your example can still be implemented as:
sequence InputData = {0.01, 0.05, 0.08, 0.03, 0.02} sequence OutputData = 1 - InputData[2..$]
But I think your point is clear - you don't want to merely use your sorted input data for a task and then reuse the unsorted version later. You don't want to just sort the output data either. You need to sort the input data for a task, then "unsort" the output data such that the each element of the output data is in the same position as the corresponding element in the original unsorted input data.
If every element is unique in the input data, and every element is unique in the output data, then you could just use mapping(). But that probably isn't true.
P.S. I've been thinking how best to implement this feature: simple or optimal. This is the easiest and most non-optimal option. There have been other attempts.
I'd go with optimal.
