Determening the nth item in a list

Lets say I have a list like this

'(a b c d e f g h i j)

How can I determin the nth of h in this list?

M

 

(defun nthof (sym lst / mlst)
(if (setq mlst (member sym lst))
(-
(length lst)
(length mlst))))

 

Marcel,

Command: (setq lst1 '(a b c d e f g h i j))
(A B C D E F G H I J)

Command: (setq lst2 (member 'h '(a b c d e f g h i j)))
(H I J)

Command: (setq indx (- (length lst1)(length lst2)))
7

Command: (nth indx lst1)
H


Bill

 

Thanx!

That was my idea too.
Just thought there might be a direct command for it.

M

 

Great minds ...

 

(vl-position)

--
R. Robert Bell


Lets say I have a list like this

'(a b c d e f g h i j)

How can I determin the nth of h in this list?

M

 

HA!
I knew it!
Not such a stupid question after all.

The less code the better. Thats my motto.

What do you say to that mister "great mind" Tom Smith? ; )

Thanx Robert.

 

What do you say to that mister "great mind" Tom Smith? ; )

I hoped you'd look back for that Marcel! I'm not fluent with all the
vl-do-this-and-that functions and gave them only a quick glance before
writing a function to do this. Leave it to Robert to know these things.

My joke to Bill was a reference was to the old expression "great minds think
alike" because we had come up with identical code independently -- it is
always used in a joking way, for instance when people happen to say the same
thing at the same time.

 

Marcel,

We're all learning something new everyday.
Most of what I've learned has been from someone showing me a better way.
That's what keeps me participating.

(vl-position 'h '(a b c d e f g h i j))

Thanks Robert.

Bill

 

why the ' ????? (vl-position 'h '(a b c d e f g h i j))

Luis, in both the vl-position function and my home-brewed equivalent, if you
don't quote the symbol, it will be evaluated. If the symbol h hasn't been
assigned a value, it evaluates to nil.

_$ (vl-position h '(a b c d e f g h i j))
nil
_$ (eval h)
nil
_$ (vl-position nil '(a b c d e f g h i j))
nil

_$ (setq newvar 'h)
H
_$ (vl-position newvar '(a b c d e f g h i j))
7
_$ (vl-position 'h '(a b c d e f g h i j))
7

 

I was just kidding Tom. All input is appreciated.
You 'd be happy to know, at first I used yours. : )
But now I use (vl-position).

M

 

I know Bill. Same for me.

FWIW

I placed a sample of the command(s) you've helped me with on the
autodesk.autocad.customer-files section.
I use it to place a variaty of symbols in- or next to a line, a groups of
symbols divided over a rectangular area or just replace a symbol.
I had written it some time ago but enhanced it with options for extra
paramters and the selection borders on the image_button.

Just thought, maby you 'd like to see what it looks like.

M

 

Unfortunatly I cannot seem to post it.

 

It is sort of a bogus list, Luis. It isn't all that often that you have a
list of symbols, but rather a list of data.

(vl-position "h" (list "a" "b" "c" "d" "e" "f" "g" "h" "i" "j"))