How to sort list of lists?

Dear Sjord,

you can try that

(sort (list '(23.5 nameA cellId) '(18.3 nameB cellId) '(73.0 nameC cellId) '(23.5 nameD cellId) '(44.9 nameE cellId)) (lambda (x y) (lessp (car x) (car y))))

Regards

Matthias

Hi,

If you want to sort the list by comparing the first elements, you can use the following command :

(sortcar your_list 'lessp)

Otherwise you just have to define a custom comparison function :

(sort your_list
  (lambda (l0 l1)
    ;; Compare l0 and l1 by first element, or by name when they are equal
    (destructuringBind (n0 name0 cell0) l0
      (destructuringBind (n1 name1 cell1) l1
        (if (equal n0 n1) (alphalessp name0 name1) (lessp n0 n1))
        ))))

Cheers,

Aurel

Hi Matthias,

Thanks for the quick response.

Your solution kind-of works. It perfectly sorts on the first element (the real), but doesn't look at the name part.

I did this:

myList = list( '(23.5 nameA cellId) '(18.3 nameB cellId) '(73.0 nameC cellId) '(23.5 nameD cellId) '(44.9 nameE cellId))
sort( myList (lambda (x y) lessp( car(x) car(y))))

And this is what the output was:

((18.3 nameB cellId)
    (23.5 nameD cellId)
    (23.5 nameA cellId)
    (44.9 nameE cellId)
    (73.0 nameC cellId)
)

As you can see, the order is correct for the first element, however, the 23.5 lists should've been the other way around:

((18.3 nameB cellId)
    (23.5 nameA cellId)
    (23.5 nameD cellId)
    (44.9 nameE cellId)
    (73.0 nameC cellId)
)

My understanding is that your solution only sorts on the first element, and doesn't take the second element into account, am I right?

Thanks for your support.

With kind regards,

Sjoerd

Sjoerd,

Take a look at Aurélien's later post which gives a sort function that uses the name as a tiebreaker.

Andrew

Hi Aurel,

Thank you for you quick response. I've tried your code and it works! It does what I'd like it to do.

I'll definitely have to spend time to understand your code (never seen the destructuringBind procedure...) and learning something, so thank you for sharing this.

With kind regards,

Sjoerd

Dear Sjord,

sorry, I did not spend enough time on reading your post.

I hope that is useful

(sort (list '(23.5 nameA cellId) '(18.3 nameB cellId) '(73.0 nameC cellId) '(23.5 nameD cellId) '(44.9 nameE cellId)) (lambda (x y) (if (equal (car x) (car y)) (alphalessp (cadr x) (cadr y)) (lessp (car x) (car y)))))


Regards

Matthias

Hi Andrew,

I've tested both solutions and the solution of Aurélien is the one I went with. Learned something new. Looking at his solution, I realized that some custom procedures I wrote can be rewritten and made way more efficient, So during the summer holiday period I'll use the less-busy times to go over my code library (=library of design team) and update where possible.

With kind regards,

Sjoerd

Hi Matthias,

Thank you for your update. Your solution looks very similar to the solution of Aurélien. Since I got the my code using the solution of Aurélien working, I'll stick to that. But I'll definitely remember your solution for the future.

Many thanks.

With kind regards,

Sjoerd