until-found

until-found

[Andreas Roehler]

Hi,

given a list or a list of lists:
list shall be returned, if it contains a certain member.

I'm pretty sure a general form exists, but ignore it.

Function `dired-compress-file' in dired-aux.el does it that way:

  (let (...
	(suffixes dired-compress-file-suffixes))
    ;; See if any suffix rule matches this file name.
    (while suffixes
      (let (case-fold-search)
	(if (string-match (car (car suffixes)) file)
	    (setq suffix (car suffixes) suffixes nil))
	(setq suffixes (cdr suffixes))))


And here my implementation so far:

(defun until-found (search-string liste)
  (let ((liste liste) element)
    (while liste
      (if (member search-string (car liste))
          (setq element (car liste) liste nil))
      (setq liste (cdr liste)))
    element))

However, would prefer making use of some existing...

Any comments welcome

Andreas

--
https://code.launchpad.net/s-x-emacs-werkstatt/
http://bazaar.launchpad.net/~a-roehler/python-mode/python-mode.el/

Re: until-found

[tomas]

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On Thu, Dec 10, 2009 at 01:50:01PM +0100, Andreas Roehler wrote:
> 
> Hi,
> 
> given a list or a list of lists:
> list shall be returned, if it contains a certain member.
> 
> I'm pretty sure a general form exists, but ignore it.

[...]

> (defun until-found (search-string liste)
>   (let ((liste liste) element)
>     (while liste
>       (if (member search-string (car liste))
>           (setq element (car liste) liste nil))
>       (setq liste (cdr liste)))
>     element))
> 

Have a look at assoc -- it might be what you are looking for.

If you need more flexibility, cl's assoc* (where you can specify, among
other things, the comparison function) might fit your bill.

Regards
- -- tomás
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Re: until-found

[Andreas Röhler]

tomas@tuxteam.de wrote:
> On Thu, Dec 10, 2009 at 01:50:01PM +0100, Andreas Roehler wrote:
>> Hi,
> 
>> given a list or a list of lists:
>> list shall be returned, if it contains a certain member.
> 
>> I'm pretty sure a general form exists, but ignore it.
> 
> [...]
> 
>> (defun until-found (search-string liste)
>>   (let ((liste liste) element)
>>     (while liste
>>       (if (member search-string (car liste))
>>           (setq element (car liste) liste nil))
>>       (setq liste (cdr liste)))
>>     element))
> 
> 
> Have a look at assoc -- it might be what you are looking for.
> 
> If you need more flexibility, cl's assoc* (where you can specify, among
> other things, the comparison function) might fit your bill.
> 
> Regards
> -- tomás

Hi Tomas,

assoc tells, it compares some key and the car of a list:

"Return non-nil if KEY is `equal' to the car of an element of LIST."

Its related, but slightly different IMO.

The form I'm looking for returns list, if an element is member of - equality
of whole list returned by car is not at stake.

Thanks anyway

Andreas

Re: until-found

[Helmut Eller]

* Andreas Roehler [2009-12-10 13:50+0100] writes:

> And here my implementation so far:
>
> (defun until-found (search-string liste)
>   (let ((liste liste) element)
>     (while liste
>       (if (member search-string (car liste))
>           (setq element (car liste) liste nil))
>       (setq liste (cdr liste)))
>     element))

This seems to be the same as:

(car (member (lambda (element) (member search-string element)) liste))

or

(find-if (lambda (element) (member search-string element)) liste)

or

(find search-string liste :test #'member)

or

(loop for e in liste if (member search-string e) return e)

Helmut

Re: until-found

[Andreas Röhler]

Helmut Eller wrote:
> * Andreas Roehler [2009-12-10 13:50+0100] writes:
> 
>> And here my implementation so far:
>>
>> (defun until-found (search-string liste)
>>   (let ((liste liste) element)
>>     (while liste
>>       (if (member search-string (car liste))
>>           (setq element (car liste) liste nil))
>>       (setq liste (cdr liste)))
>>     element))
> 
> This seems to be the same as:
> 
> (car (member (lambda (element) (member search-string element)) liste))
> 
> or
> 
> (find-if (lambda (element) (member search-string element)) liste)
> 
> or
> 
> (find search-string liste :test #'member)
> 
> or
> 
> (loop for e in liste if (member search-string e) return e)
> 
> Helmut
> 

Ah, fine stuff, thanks a lot!

Andreas