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Diffstat (limited to 'doc/lispref/lists.texi')
| -rw-r--r-- | doc/lispref/lists.texi | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/doc/lispref/lists.texi b/doc/lispref/lists.texi index 75641256b60..f98ae76da9a 100644 --- a/doc/lispref/lists.texi +++ b/doc/lispref/lists.texi @@ -1227,13 +1227,13 @@ this is not guaranteed to happen): @cindex lists as sets @cindex sets - A list can represent an unordered mathematical set---simply consider a -value an element of a set if it appears in the list, and ignore the -order of the list. To form the union of two sets, use @code{append} (as -long as you don't mind having duplicate elements). You can remove -@code{equal} duplicates using @code{delete-dups}. Other useful -functions for sets include @code{memq} and @code{delq}, and their -@code{equal} versions, @code{member} and @code{delete}. + A list can represent an unordered mathematical set---simply consider +a value an element of a set if it appears in the list, and ignore the +order of the list. To form the union of two sets, use @code{append} +(as long as you don't mind having duplicate elements). You can remove +@code{equal} duplicates using @code{delete-dups} or @code{seq-uniq}. +Other useful functions for sets include @code{memq} and @code{delq}, +and their @code{equal} versions, @code{member} and @code{delete}. @cindex CL note---lack @code{union}, @code{intersection} @quotation @@ -1489,7 +1489,8 @@ comparison. This function destructively removes all @code{equal} duplicates from @var{list}, stores the result in @var{list} and returns it. Of several @code{equal} occurrences of an element in @var{list}, -@code{delete-dups} keeps the first one. +@code{delete-dups} keeps the first one. See @code{seq-uniq} for +non-destructive operation (@pxref{Sequence Functions}). @end defun See also the function @code{add-to-list}, in @ref{List Variables}, |