subsetp list-1 list-2 &key key test test-not ⇒ generalized-boolean
| list-1 | a proper list. |
| list-2 | a proper list. |
| test | a designator for a function of two arguments that returns a generalized boolean. |
| test-not | a designator for a function of two arguments that returns a generalized boolean. |
| key | a designator for a function of one argument, or nil. |
| generalized-boolean | a generalized boolean. |
subsetp returns true if every element of list-1 matches some element of list-2, and false otherwise.
Whether a list element is the same as another list element is
determined by the functions specified by the keyword arguments.
The first argument to the :test or :test-not
function is
typically
part of an element of list-1 extracted by
the :key function; the second argument is typically part of
an element of list-2 extracted by
the :key function.
The argument to the :key function is an element of either
list-1 or list-2; the return value is part of the element
of the supplied list element.
If :key is not supplied or nil,
the list-1 or list-2
element itself is supplied to the :test or :test-not
function.
(setq cosmos '(1 "a" (1 2))) ⇒ (1 "a" (1 2))
(subsetp '(1) cosmos) ⇒ true
(subsetp '((1 2)) cosmos) ⇒ false
(subsetp '((1 2)) cosmos :test 'equal) ⇒ true
(subsetp '(1 "A") cosmos :test #'equalp) ⇒ true
(subsetp '((1) (2)) '((1) (2))) ⇒ false
(subsetp '((1) (2)) '((1) (2)) :key #'car) ⇒ true
Should be prepared to signal an error of type type-error if list-1 and list-2 are not proper lists.
The :test-not parameter is deprecated.