diff options
author | Dave Love <fx@gnu.org> | 2001-01-05 16:56:21 +0000 |
---|---|---|
committer | Dave Love <fx@gnu.org> | 2001-01-05 16:56:21 +0000 |
commit | 023045d66ddef29afa17245d4de14b9d77915f5a (patch) | |
tree | 3f8de79c7046ec9db6149ed39261c9b5e72524f5 /lispref | |
parent | 2d4c95097a4fb7601070751e9d444eb3bcad467a (diff) | |
download | emacs-023045d66ddef29afa17245d4de14b9d77915f5a.tar.gz |
butlast, nbutlast.
Diffstat (limited to 'lispref')
-rw-r--r-- | lispref/lists.texi | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/lispref/lists.texi b/lispref/lists.texi index 222f723944f..6ae9e68d402 100644 --- a/lispref/lists.texi +++ b/lispref/lists.texi @@ -422,6 +422,20 @@ This is the same as @code{(cdr (cdr @var{cons-cell}))} or @code{(nthcdr 2 @var{cons-cell})}. @end defun +@defun butlast x &optional n +This function returns the list @var{x} with the last element, +or the last @var{n} elements, removed. If @var{n} is greater +than zero it makes a copy of the list so as not to damage the +original list. In general, @code{(append (butlast @var{x} @var{n}) +(last @var{x} @var{n}))} will return a list equal to @var{x}. +@end defun + +@defun nbutlast x &optional n +This is a version of @code{butlast} that works by destructively +modifying the @code{cdr} of the appropriate element, rather than +making a copy of the list. +@end defun + @node Building Lists @comment node-name, next, previous, up @section Building Cons Cells and Lists |