Lisp: Extract highest/lowest value from a list

O.K, If I have a list, is there a function that will allow me to extract the highest value and/or lowest value?

I don't care about duplicates.

In thinking about this, I could probably accomplish this task by using nth values and performing comparisons but that seems tedious. I was hoping I could do it in a single shot with a function.

Sample:

(setq MyList ((2.00000 26.0000 26.0000 25.6250 25.6250 3.00000 3.00000 2.00000))

This is what I'm after:

(setq LowVal (MyList))

(setq HighVal(MyList))

Thanks again for any help

---AJS

ajs,

From your questions, you really need to get a reference with all the lisp functions to scan through, even search.

See 'max & 'min functions....

Thanks for the reply. I think you're right about the search function. I do have a function list but sometimes after reading it over and over, I find that I will (through carelessness) skip over something.

An example would be my earlier question on length, for some reason, I thought that the length function applied to strings and thus I didn't examine it properly.

I'm going to go online and see if I can find a searchable lisp function list.

I do appreciate the help of course. Thank you

---AJS

You're welcome.

A summary of fiuctions, alphabetical & by category is at http://ronleigh.info/autolisp/acatalog.htm

The reference "alispref.pdf" is quite handy, I'd upload it except it's much larger than allowed at this site, maybe you can find it elsewhere...

Command: (apply 'min '(4 6 1 8 0.5 12))
0.5

Command: (apply 'max '(4 6 1 8 0.5 12))
12.0

The function MAX doesn´t seem to work with a already defined list of reals, eg:

Command: !(Setq A '(1.0 1.2 2.1 3.4))

(1.0 1.2 2.1 3.4))

Command: !(Max A)

; error: bad argument type: numberp: (1.0 1.2 2.1 3.4)

Command: !(Apply 'Max A)

; error: bad argument type: numberp: (1.0 1.2 2.1 3.4)

Any sugestion??

Worked for me

Command: (Setq A '(1.0 1.2 2.1 3.4))

(1.0 1.2 2.1 3.4)

 

Command: (apply 'max a)

3.4

Hey ajs

There is no need to use the ! if you are defining a function on the command line

Command: !(Setq A '(1.0 1.2 2.1 3.4))

Just use as lpseifert has shown

Command: (Setq A '(1.0 1.2 2.1 3.4))

(1.0 1.2 2.1 3.4)

 

Command: (apply 'max a)

3.4

I don't mean to hijack this thread, but (somewhat related) how would I obtain values that are repeated in a list?

e.g. (setq list1 (a b b c)) - how do you extract the value of b?

Thanks, for help.

The function work fine. I had a problem, because my list has a 'nil' element.

I don't mean to hijack this thread, but (somewhat related) how would I obtain values that are repeated in a list?

 

e.g. (setq list1 (a b b c)) - how do you extract the value of b?

I'm not sure if there is a straight-forward function to detect this... I would be inclined to make a comparison between every item in the list and make a list of items already "viewed".

Perhaps something like this:

(defun getrep (alist)
 (foreach x alist
   (if (member x nlist)
     (setq dlist (cons x dlist))
     (setq nlist (cons x nlist))))
 dlist)

(defun c:test ()
 (alert (vl-princ-to-string (getrep '(a b c c d e f f g))))
 (princ))

another way:

(eval(cons 'max a))

(eval(cons 'min a))

If you sort the list then items the same will be next to each other so you can do things like count them up or delete duplicates.