Topic: remove elements from a list with identifier of sub-list (recursive)

[robertocuba]

Hello:

Iīm developing a following routine to remove elements from a list between identifiers "x" .... "x" of sub-list (recursive).

Problem:
List: ("a" 3 4 5 5 "b" 8 7 6 3 2 2 1 1 "c" 5 67 87 76 "d" 9 0 5 49 5 9)

The routine must be return:

List:  ("a" 3 4 5 "b" 8 7 6 3 2 1 "c" 5 67 87 76 "d" 9 0 5 49)

Thanks !

[MP]

Post the code you've developed so far.

[uncoolperson]

from your example I'm having trouble understanding what you want to remove.

in three instances duplicated items have one removed
then there's the items at the end that are removed

[robertocuba]

Yes, I want remove the similar elements, between "a" and "b", and between "b" and " and ...

[MP]

It appears to me that alpha characters are delimiters, anything before, between or after are subgroups, and the OP's want is to have each subgroup sport unique members. I'm getting a strong impression these exercises are actually homework assignments, and as much as I enjoy challenges, I have no interest if they are indeed homework. Of course I'm open to hearing an alternative explanation and viewing the OP's attempts thus far.

[uncoolperson]

it was fun solving though.

[MP]

Agreed.

Mine's a bit verbose at 14 lines.

[uncoolperson]

3 recursives, not very streamlined... way too many lines that look similar and are begging to be condensed. it was fun to think through.

[gile]

14 lines too (vlisp formated), only one recursive sub

[JohnK]

Ummm...*Se7en: scratches head* ...why recursive?

And if this is homework then; `recursive' describes the procedure not necessarily the type of process. So what kind of process? -i.e. you want a ``Recursive procedure using a ______ process which will remove the elements....''?

[gile]

11 lines, but need to call (foo lst nil)

[uncoolperson]

you know I've never understood counting lines in lisp.

I mean in theory mine could be 3 lines.


(sorry, just trying to make me feel better about myself)

[JohnK]

<snip>
I mean in theory mine could be 3 lines.
<snip>

In theory,  it could be one. *lol*

[MP]

11 lines, but need to call (foo lst nil)

Bizarro world: same here but 12 lines, 15 with the wrapper.

1 line if I skip the superfluous carriage returns. 

[robertocuba]

The code?

Thanks !