first,second,third,forth,fifth,sixth, ..., rest | ![]() |
Better as NTH
, CAR
or CDR
.
They return the first second and so on, elements of list. Same as (CAR
lst), (CADR
lst), ...
REST
returns the rest after the first element of the list, same as (CDR
lst).
They should be used instead of CAR
, CADR
, ... for lists to improve the readability of the code.
Secondly they will not fail on too short lists which is useful for accessing lists as structures and keeping structures short, using optional slots which default to nil.
But for points better use: X-OF, Y-OF
and Z-OF.
Difference to NTH
In short: To get the fourth element of a list better use (FOURTH
lst) then (NTH
3 lst)
They accept nil as argument too, which is better than NTH
.
(NTH
3 lst) looks like (FOURTH
lst), but is NOT the same, because (NTH
3 nil) will throw an error, but (FOURTH
nil) will return nil.
list: any list, including not proper lists
The specified element(s) of the list or nil.
None.
(std-require 'STDLIST)
Defined in STDLIST
Parts are #- SMALL