Re: Problem with position and find (cl)

[Marc Tfardy <m-t-o___CUT__IT@web.de>]

Marc Tfardy schrieb:
> Thierry Volpiatto schrieb:
>> Florian Beck <abstraktion@t-online.de> writes:
>>
>>> Marc Tfardy <m-t-o___CUT__IT@web.de> writes:
>>>
>>>> Marc Tfardy schrieb:
>>>>> I try with:
>>>>> (member '(2) '((1) (2) (3) (4)))
>>> `member' tests the components: ›2‹ ist always equal (in the sense of 
>>> »eq«) to ›2‹
>>>
>>> Compare:
>>>
>>> (memq '(2) '((1) (2) (3) (4)))
>>> (eq 2 2)
>>> (eq '(2) '(2))
>>>
>>>>> and this gives a expectet results ((2) (3) (4)), but:
>>>>> (find '(2) '((1) (2) (3) (4)))
>>>>> or
>>>>> (position '(2) '((1) (2) (3) (4)))
>>>>>
>>>>> returns nil. Why?
>>> Because  the first and the second »(2)« have the same components but are
>>> *different* lists.
>>>
>>>> But this works:
>>>>
>>>> (position '(2) '((1) (2) (3) (4)) :test (lambda (x y) (eq (car x) (car
>>>> y))))
>>>>
> 
>> position default test is 'eq, try 'equal
> 
> Thanks! It works with equal. But I have another problem.
> find (and find-if) returns only first match. Is there another
> function that returns all matched elements. Some example:
> 
> (find-if-all (lambda (x) (if (eq (nth 2 x) 'byte) t nil)) '((1.1 "x" 
> int) (2.2 "y" byte) (3.3 "q" int) (4.4 "b" byte) (5.5 "a" float)))
> 
> should returns:
> ((2.2 "y" byte) (4.4 "b" byte))
> 
> I found in cl-*.el nothing like this. Any hints?


I found some "strange" solution:

(remove-if-not (lambda (x) (if (eq (nth 2 x) 'byte) t nil)) '((1.1 "x" 
int) (2.2 "y" byte) (3.3 "q" int) (4.4 "b" byte) (5.5 "a" float)))

but with:
(fset 'find-all 'remove-if-not)
or:
(defalias 'find-all 'remove-if-not)

(a propos - what is the right method?) - it looks good and
works like expected.

Marc