Topic: How to delete "" nil in the list (1245 "" "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8

[jxphklibin]

How to delete "" nil in the list (1245 "" "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9))

_$ (list 1245 "" nil "add" '(1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9))
(1245 "" "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9))

_$ (vl-list* 1 "" 2 NIL "" 3 5 "" NIL 6 "" 8  9)
(1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9)

[Kerry]

not pretty, but seems to work ..

Code: [Select]

(setq myList  (list 1245 "" nil "add" "" '(1 "" 2 nil "" 3 5 "" nil 6 "" 8.9))
      string  (vl-prin1-to-string myList)
      pattern (vl-prin1-to-string "")
)


(while (setq index (vl-string-search pattern string 0))
    (setq string (vl-string-subst "" pattern string))
)
(setq pattern (vl-prin1-to-string nil))
(while (setq index (vl-string-search pattern string 0))
    (setq string (vl-string-subst "" pattern string))
)

(setq NewList (read string))

;;=> (1245 "add" (1 2 3 5 6 8.9))

[Kerry]

oh, wait ..

[forestgump]
'pretty is as pretty does'
[/gump]

[gile]

Hi,

Another way

<EDIT>: corrected an error if some members of the last dotted pair have to be removed.

Code: [Select]

(defun nested-remove-if (fun lst / ele)
  (if lst
    (if (listp (cdr lst))
      (if (atom (setq ele (car lst)))
(if (apply fun (list ele))
  (nested-remove-if fun (cdr lst))
  (cons ele (nested-remove-if fun (cdr lst)))
)
(list (nested-remove-if fun ele))
      )
      (if (apply fun (list (car lst)))
(if (not (apply fun (list (cdr lst))))
  (cdr lst)
)
(if (apply fun (list (cdr lst)))
  (list (car lst))
  lst
)
      )
    )
  )
)
_$ (setq lst '(1245 "" "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9)))
(1245 "" "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9))
_$ (n-remove-if '(lambda (x) (member x '("" nil))) lst)
(1245 "add" (1 2 3 5 6 8 . 9))

[SomeCallMeDave]

Gile's post gave the nudge I needed to get this one to work.  Merci, Gile.

Code: [Select]


(defun ShouldIGo(x)
     (if (member x '("" nil)) T nil)
)     

(setq myList '(1245 "" nil "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8.9)))     

(setq myNewList (vl-remove-if 'ShouldIGo (mapcar '(lambda (x) (if (listp x) (vl-remove-if 'ShouldIGo  x) x)) myList)))



[SomeCallMeDave]

.... corrected an error if some members of the last dotted pair have to be removed.
...

Is that a dotted pair or a decimal number?

Mine will not work if it is a dotted pair

[gile]

Is that a dotted pair or a decimal number?

Mine will not work if it is a dotted pair

In jxphklibin's list the nested list is a dotted list built with vl-list*, it's why I built my own recursive function instead of using a mapcar statement (it's needed to test if the last cdr is an atom or a list)

[CAB]

One would have to ask jxphklibin if the dotted list is your intention & for what pourpose.

[jxphklibin]

Nice , Kerry Brown , gile.
Thanks!

I just find a way to deal with it, no intention & no pourpose. Since there is possible existence of  the dotted list. At the same time, also let me know to delete the specified elements of the list (including nested list) in another way. You are very nice！Thanks again!!!

[jxphklibin]

Hi,

Another way

<EDIT>: corrected an error if some members of the last dotted pair have to be removed.

Code: [Select]

(defun nested-remove-if (fun lst / ele)
  (if lst
    (if (listp (cdr lst))
      (if (atom (setq ele (car lst)))
(if (apply fun (list ele))
  (nested-remove-if fun (cdr lst))
  (cons ele (nested-remove-if fun (cdr lst)))
)
(list (nested-remove-if fun ele))
      )
      (if (apply fun (list (car lst)))
(if (not (apply fun (list (cdr lst))))
  (cdr lst)
)
(if (apply fun (list (cdr lst)))
  (list (car lst))
  lst
)
      )
    )
  )
)
_$ (setq lst '(1245 "" "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9)))
(1245 "" "add" (1 "" 2 nil "" 3 5 "" nil 6 "" 8 . 9))
_$ (n-remove-if '(lambda (x) (member x '("" nil))) lst)
(1245 "add" (1 2 3 5 6 8 . 9))

Hi,gile
When the list is:
 (list 1245 "" nil "add" "" (list 1 "" 2 nil "" 3 5 "" nil 6 "" 8 9 (list 888 888 "" nil 9999 9999 nil "") 555 "" nil 666) 777 "" nil 77777)
, then it doesn't work correctly! But Kerry Brown's work correctly!

[gile]

Oopss

Code: [Select]

(defun nested-remove-if (fun lst / ele)
  (if lst
    (if (listp (cdr lst))
      (if (atom (setq ele (car lst)))
(if (apply fun (list ele))
  (nested-remove-if fun (cdr lst))
  (cons ele (nested-remove-if fun (cdr lst)))
)
(cons (nested-remove-if fun ele)
      (nested-remove-if fun (cdr lst))
)
      )
      (if (apply fun (list (car lst)))
(if (not (apply fun (list (cdr lst))))
  (cdr lst)
)
(if (apply fun (list (cdr lst)))
  (list (car lst))
  lst
)
      )
    )
  )
)

[JohnK]

Forgive me but may i ask why are you removing the "NIL" from the lists, can't you just ignore them?
I ask because it seems like removing them would take more effort then need be.

[MP]

Code: [Select]

(defun deflate ( x / a )
    (cond
        ((atom x) x)
        ((null (vl-consp x)) (if (vl-every 'atom x)(vl-remove-if 'null x)(mapcar 'deflate x)))
        ((setq a (car x)) (cons (deflate a) (deflate (cdr x))))
        ((deflate (cdr x)))
    )
)

Forgive me but may i ask why are you removing the "NIL" from the lists, can't you just ignore them?
I ask because it seems like removing them would take more effort then need be.

It's play time for nerds, get with the program.

[JohnK]

> It's play time for nerds, get with the program.
*lol*

Here is mine i guess.

Code: [Select]

(setq mylist '(list ((1245 "" ((nil "add" (""))))) (list 1 "" 2 nil "" 3 5 "" nil 6 "" 8 9 (list 888 888 "" nil 9999 9999 nil "") 555 "" nil 666 777 "" nil) 77777))

(killer-n mylist "")

(defun killer-n (x a)
    (if (atom x)
      (if (not (eq a x)) x)
      (vl-remove-if 'null
(cons (killer-n (car x) a)
            (killer-n (cdr x) a)))))

[ElpanovEvgeniy]

my variant:

Code: [Select]

(defun f (l)
 (cond ((null l) nil)
       ((atom l) (list l))
       ((listp l) (append (f (car l)) (f (cdr l))))
 ) ;_  cond
) ;_  defun