Why

_$ (subst 9 3 (list 1 2 3 4 5))
(1 2 9 4 5)
_$ (subst 3 1 (list 28.3367 8.75775 0.0))
(28.3367 8.75775 0.0)
_$

Any comment ?

 

Comment on what?

Isn't the purpose of the function clear?

 

in the 1st example (subst 9 3 (list 1 2 3 4 5)) returns (1 2 9 4 5)
the program "substituted" 9 for each occurrence of 3 (only 1 in this case)
for example -(subst 9 3 (list 1 2 3 4 5 3)) returns (1 2 9 4 5 9)

in the 2nd example (subst 3 1 (list 28.3367 8.75775 0.0)) returns (28.3367
8.75775 0.0)
because there were no "1" in the list so the program returned the original
list

by the way, (subst 9 3 (list 28.3367 8.75775 0.0)) would NOT return (28.9967
8.75775 0.0)
for example - (subst 3 28.3367 (list 28.3367 8.75775 0.0)) returns (3
8.75775 0.0)
another example - (subst "A" "a" (list "a" "b" "c" "abc")) returns ("A" "b"
"c" "abc")

Tony, he obviously does NOT get the function. I believe there might be a
language barrier that Adesu is having a problem with, if you look at many of
his recent posts. Just because it is obvious to you does not mean something
should be obvious to everyone else.

 

Comment on what?

I think he would like to see

_$ (subst 3 1 (list 28.3367 8.75775 0.0))
(28.1167 8.75775 0.0) (note the 1's)
instead of the usual.
_$ (subst 3 1 (list 28.3367 8.75775 0.0))
(28.3367 8.75775 0.0)
If I'm wrong, I'm also stumped as to what he wants.
Dr Fleau

 

(setq ent1 (list 28.3367 8.75775 0.0))
(28.3367 8.75775 0.0)
_$ (subst 3 (nth 0 ent1) ent1)
(3 8.75775 0.0)

Hi Alan,thanks a lot for your advice,I've understood it,before that I
thought ;
(subst 9 3 (list 1 2 3 4 5))
value "3" is for replace no.third from list,I wrong guess !