List of lists: How to add elements to each sub-list?

Hi,

It may depend how you are 'finding' or specifying which sublist to add to.  Here's a brief example:

nlist = '((1 2) (4 5))
=> ((1 2) (4 5))

; find the list starting with '1'
assoc(1 nlist)
=> (1 2)

; destructively append to that sub-list (i.e. edit it in place)
nconc(assoc(1 nlist) '(3))
=> (1 2 3)

; inspect the list
nlist
=> ((1 2 3) (4 5))

; find the list starting with '4'
assoc(4 nlist)
=> (4 5)

;destructively append to that sub-list
nconc(assoc(4 nlist) '(6))
=> (4 5 6)

nlist
=> ((1 2 3) (4 5 6))

Hopefully this helps?

Best regards,

Lawrence.

hmmmh...depends from what element you want to append to each sublist. Here is an example for appending the same element to each sublist using the  destructive nconc() and the setf function (which I believe is technically a macro):

ll='((2 3) (4 5) (6 7))
(for i 0 (length ll)-1
   (setf (nth i ll)
      (nconc (nth i ll) '(99)))
)

...the above append '99' to each sublist.