zl:1 - FTP

363 nintersection
(loop-never '(b c a e) => (8 C A E)
(loop-never '(a a»
=> A NIL
See the section "loop Clauses", page 310.
nintersection listl list2 &key (test #'eqI) test-not (key #'identity) Function
nintersection is the destructive version of intersection. intersection takes
listl and list2 and returns a new list containing everything that is an element
of both lists. nintersection performs the same operation, but uses
the cells of listl to construct the result. The value of list2 is not altered.
The keywords are:
:test
:test-not
:key
Any predicate specifying a binary operation to be applied
to a supplied argument and an element of a target list.
The item matches the specification only if the predicate
returns t. If :test is not supplied the default operation is
eql.
Similar to :test, except the item matches the specification
only if there is an element of the list for which the
predicate returns nil.
If not nil, should be a function of one argument that will
extract from an element the part to be tested in place of
the whole element.
See the function intersection, page 277. For example:
(setq a-list '(a be» => (A 8 C)
I
(setq b-list '(f a d» => (F A 0)
(nintersection a-list b-list) => (A)
a-list => (A)
b-list => (F A 0)
For a table of related items: See the section "Functions for Comparing
Lists" in Symbolics Common Lisp: Language Concepts.
zl:nintersection &rest lists Function
Takes any number of lists that represent sets and returns a new list that
represents the intersection of all the sets it is given, by destroying any of
the lists passed as arguments and reusing the conses. zl:nintersection
uses eq for its comparisons. You cannot change the function used for the
comparison. (zl:nintersection) returns nil.