Rearranging lists in lisp

From: Mike Weston
Subject: Rearranging lists in lisp
Date: Wed, 20 Jun 2001 13:25:30 +0000
Message-ID: <fd5c9a54.0106200525.58cf7cfe@posting.google.com>

Hi,

I am having a problem rearranging a list into a specified order and
wondered if anyone could help?  I want to sort the list by the 9th
character (e.g. F in 'CEI2110.FC2) by a preset order I, R, C, F

('CEI2110.IL2 'CEI2110.IL1 'CEI2110.FC2 'CEI2110.FC1 'CEI1001.R
'CEi4070.C)

=> ('CEI2110.IL1 'CEI2110.IL2 'CEI1001.R 'CEI4070.C 'CEI2110.FC1
'CEI2110.FC2)

Thanks

Mike

Re: Rearranging lists in lisp Coby Beck
Re: Rearranging lists in lisp Tim Bradshaw
Re: Rearranging lists in lisp Raymond Wiker
Re: Rearranging lists in lisp Friedrich Dominicus
Re: Rearranging lists in lisp ···············@solibri.com
Re: Rearranging lists in lisp Mike Weston

From: Coby Beck
Subject: Re: Rearranging lists in lisp
Date: Wed, 20 Jun 2001 13:41:08 +0000
Message-ID: <UJ1Y6.25644$_T2.5672389@typhoon.tampabay.rr.com>

"Mike Weston" <················@bnfl.com> wrote in message
·································@posting.google.com...
> Hi,
>
> I am having a problem rearranging a list into a specified order and
> wondered if anyone could help?  I want to sort the list by the 9th
> character (e.g. F in 'CEI2110.FC2) by a preset order I, R, C, F

What have you got so far?

Coby

(remove #\space "coby . beck @ opentgi . com")

From: Tim Bradshaw
Subject: Re: Rearranging lists in lisp
Date: Wed, 20 Jun 2001 13:45:21 +0000
Message-ID: <nkjsngvs1se.fsf@tfeb.org>

················@bnfl.com (Mike Weston) writes:

> Hi,
> 
> I am having a problem rearranging a list into a specified order and
> wondered if anyone could help?  I want to sort the list by the 9th
> character (e.g. F in 'CEI2110.FC2) by a preset order I, R, C, F

This can't be a homework problem, unless you are doign a weird course!

If the lists are really like this:

(CEI2110.IL2 CEI2110.IL1 CEI2110.FC2 CEI2110.FC1 CEI1001.R
 CEi4070.C)

(no quotes in there), then something like this might help.

(defun obscuro-sort (l &key 
                       (index 8)
                       (coding '((#\I . 0)
                                 (#\R . 1)
                                 (#\C . 2)
                                 (#\F . 3))))
  ;; destructive of L, probably
  ;; L is a list of symbols with names with at least index+1 chars.
  (sort l #'< :key #'(lambda (s)
                       (let ((c (aref (symbol-name s) index)))
                         (or (cdr (assoc c coding))
                             ;; uncoded things wil sort at the start.
                             -1)))))

--tim

From: Raymond Wiker
Subject: Re: Rearranging lists in lisp
Date: Wed, 20 Jun 2001 13:52:35 +0000
Message-ID: <86y9qns1gc.fsf@raw.grenland.fast.no>

················@bnfl.com (Mike Weston) writes:

> Hi,
> 
> I am having a problem rearranging a list into a specified order and
> wondered if anyone could help?  I want to sort the list by the 9th
> character (e.g. F in 'CEI2110.FC2) by a preset order I, R, C, F
> 
> ('CEI2110.IL2 'CEI2110.IL1 'CEI2110.FC2 'CEI2110.FC1 'CEI1001.R
> 'CEi4070.C)
> 
> => ('CEI2110.IL1 'CEI2110.IL2 'CEI1001.R 'CEI4070.C 'CEI2110.FC1
> 'CEI2110.FC2)
> 
> Thanks
> 
> Mike

        The following appears to work, but (probably) needs to be made
more robust. 

* (let ((order #(#\I #\R #\C #\F)))
    (defun mw-< (a b)
      (labels ((key (x)
	         (char (if (symbolp x) (symbol-name x) x) 8))
	       (rank (x)
	         (position (key x) order)))
        (< (rank a) (rank b)))))
; converted MW-<

MW-<
* (sort '(CEI2110.IL2 CEI2110.IL1 CEI2110.FC2 CEI2110.FC1 CEI1001.R CEi4070.C)
        #'mw-<)
(CEI2110.IL2 CEI2110.IL1 CEI1001.R CEI4070.C CEI2110.FC2 CEI2110.FC1)
* 

-- 
Raymond Wiker
·············@fast.no

From: Friedrich Dominicus
Subject: Re: Rearranging lists in lisp
Date: Wed, 20 Jun 2001 14:45:45 +0000
Message-ID: <87elsfciqu.fsf@frown.here>

················@bnfl.com (Mike Weston) writes:

> Hi,
> 
> I am having a problem rearranging a list into a specified order and
> wondered if anyone could help?  I want to sort the list by the 9th
> character (e.g. F in 'CEI2110.FC2) by a preset order I, R, C, F
> 
> ('CEI2110.IL2 'CEI2110.IL1 'CEI2110.FC2 'CEI2110.FC1 'CEI1001.R
> 'CEi4070.C)
> 
> => ('CEI2110.IL1 'CEI2110.IL2 'CEI1001.R 'CEI4070.C 'CEI2110.FC1
> 'CEI2110.FC2)
check out sort

sligtly modified list
(setq test-list '("CEI2110.IL2" "CEI2110.IL1" "CEI2110.FC2" 
                   "CEI2110.FC1" "CEI1001.R" "CEI4070.C"))

(have used Strings instead of symbols but even with symbols one can do
that)

(defun my-rearrange (list-of-strings)
                   (flet ((cmp-func (ch1 ch2)
                              (let ((in-list '(#\I #\R #\C #\F)))
                                 (assert (and (member ch1 in-list)
                                              (member ch2 in-list)))
                                 (if (<= (position ch1 in-list :test #'char=)
                                         (position ch2 in-list :test #'char=))
                                   t
                                  nil))))
                            (sort list-of-strings 
              #'(lambda(str1 str2) (cmp-func (char str1 8) (char str2 8))))))


Regards
Friedrich

From: ···············@solibri.com
Subject: Re: Rearranging lists in lisp
Date: Wed, 20 Jun 2001 14:01:01 +0000
Message-ID: <uk8279roi.fsf@solibri.com>

················@bnfl.com (Mike Weston) writes:

> Hi,
> 
> I am having a problem rearranging a list into a specified order and
> wondered if anyone could help?  I want to sort the list by the 9th
> character (e.g. F in 'CEI2110.FC2) by a preset order I, R, C, F
> 
> ('CEI2110.IL2 'CEI2110.IL1 'CEI2110.FC2 'CEI2110.FC1 'CEI1001.R
> 'CEi4070.C)
> 
> => ('CEI2110.IL1 'CEI2110.IL2 'CEI1001.R 'CEI4070.C 'CEI2110.FC1
> 'CEI2110.FC2)




http://www.xanalys.com/software_tools/reference/HyperSpec/Body/fun_sortcm_stable-sort.html

--

From: Mike Weston
Subject: Re: Rearranging lists in lisp
Date: Thu, 21 Jun 2001 09:13:59 +0000
Message-ID: <fd5c9a54.0106210113.7158a0ec@posting.google.com>

Thanks for your help.

--mike