summaryrefslogtreecommitdiff
path: root/lispref/lists.texi
diff options
context:
space:
mode:
authorGerd Moellmann <gerd@gnu.org>2000-08-15 13:22:09 +0000
committerGerd Moellmann <gerd@gnu.org>2000-08-15 13:22:09 +0000
commitf68446efd37a6ee25e8ed0f14231bfe457aaeb9d (patch)
tree3b63dcc5a5a173f1ff6a4aeb0df786de2bcca4c1 /lispref/lists.texi
parent9105187020025123f64e48f2f735babb329cd09a (diff)
*** empty log message ***
Diffstat (limited to 'lispref/lists.texi')
-rw-r--r--lispref/lists.texi74
1 files changed, 64 insertions, 10 deletions
diff --git a/lispref/lists.texi b/lispref/lists.texi
index 661c8c3530..64e634d280 100644
--- a/lispref/lists.texi
+++ b/lispref/lists.texi
@@ -663,6 +663,31 @@ x
@end example
@end defun
+@defun remq object list
+This function returns a copy of @var{list}, with all elements removed
+which are @code{eq} to @var{object}. The letter @samp{q} in @code{remq}
+says that it uses @code{eq} to compare @var{object} against the elements
+of @code{list}.
+
+@example
+@group
+(setq sample-list '(a b c a b c))
+ @result{} (a b c a b c)
+@end group
+@group
+(remq 'a sample-list)
+ @result{} (b c b c)
+@end group
+@group
+sample-list
+ @result{} (a b c a b c)
+@end group
+@end example
+@noindent
+The function @code{delq} offers a way to perform this operation
+destructively. See @ref{Sets And Lists}.
+@end defun
+
@node Modifying Lists
@section Modifying Existing List Structure
@cindex destructive list operations
@@ -1162,7 +1187,7 @@ compare @var{object} against the elements of the list. For example:
This function destructively removes all elements @code{eq} to
@var{object} from @var{list}. The letter @samp{q} in @code{delq} says
that it uses @code{eq} to compare @var{object} against the elements of
-the list, like @code{memq}.
+the list, like @code{memq} and @code{remq}.
@end defun
When @code{delq} deletes elements from the front of the list, it does so
@@ -1252,25 +1277,54 @@ Compare this with @code{memq}:
@end example
@end defun
-@defun delete object list
-This function destructively removes all elements @code{equal} to
-@var{object} from @var{list}. It is to @code{delq} as @code{member} is
-to @code{memq}: it uses @code{equal} to compare elements with
-@var{object}, like @code{member}; when it finds an element that matches,
-it removes the element just as @code{delq} would. For example:
+@defun delete object sequence
+If @code{sequence} is a list, this function destructively removes all
+elements @code{equal} to @var{object} from @var{sequence}. For lists,
+@code{delete} is to @code{delq} as @code{member} is to @code{memq}: it
+uses @code{equal} to compare elements with @var{object}, like
+@code{member}; when it finds an element that matches, it removes the
+element just as @code{delq} would.
+
+If @code{sequence} is a vector or string, @code{delete} returns a copy
+of @code{sequence} with all elements @code{equal} to @code{object}
+removed.
+
+For example:
@example
@group
(delete '(2) '((2) (1) (2)))
@result{} ((1))
@end group
+@group
+(delete '(2) [(2) (1) (2)])
+ @result{} [(1)]
+@end group
+@end example
+@end defun
+
+@defun remove object sequence
+This function is the non-destructive counterpart of @code{delete}. If
+returns a copy of @code{sequence}, a list, vector, or string, with
+elements @code{equal} to @code{object} removed. For example:
+
+@example
+@group
+(remove '(2) '((2) (1) (2)))
+ @result{} ((1))
+@end group
+@group
+(remove '(2) [(2) (1) (2)])
+ @result{} [(1)]
+@end group
@end example
@end defun
@quotation
-@b{Common Lisp note:} The functions @code{member} and @code{delete} in
-GNU Emacs Lisp are derived from Maclisp, not Common Lisp. The Common
-Lisp versions do not use @code{equal} to compare elements.
+@b{Common Lisp note:} The functions @code{member}, @code{delete} and
+@code{remove} in GNU Emacs Lisp are derived from Maclisp, not Common
+Lisp. The Common Lisp versions do not use @code{equal} to compare
+elements.
@end quotation
See also the function @code{add-to-list}, in @ref{Setting Variables},