List Commands Library for 50g

[DavidM]

(09-27-2017 11:47 AM)John Keith Wrote:  

(09-26-2017 03:29 PM)DavidM Wrote:  Wouldn't GoferList's FindIndex work for this?

I can't see how. You can use Find or FindIndex to find the first element in the list that is within a certain amount of the desired value. Assuming the value you are searching for is in the variable n, you can do something like this:

Code:

\<< n - ABS .01 < \>> FindIndex

which will find the index of the first element that is within .01 of the value of n, or 0. if no element meets that criterion.

To find the closest value you can use the ListExt command KSORT like so:

Code:

DUP n - ABS KSORT HEAD SWAP HEAD

I was doing a mental translation of Pier's request into what I thought he was trying to do in the other thread, which was looking for the largest number in the list which was still smaller than the target. I believe that is still doable with Find/FindIndex (you may need to reverse the list first, though).

John's solution is more accurate to the actual request Pier made, though.

KSORT is really just a "helper command" that combines two lists into a "list of lists" for either the built-in SORT or a program of your own choosing, then returns the lists to their original (but newly sorted) grouping. I haven't tried to reinvent the code for sorting, especially since Werner already did such a wonderful job with LSORT.