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S9 LIB (position object list) ==> integer | #f
(posv object list) ==> integer | #f
(posq object list) ==> integer | #f
(posp procedure object list) ==> integer | #f
Find the position of an object in a list. When LIST contains OBJECT,
return the position of OBJECT (where the first object is as position
zero) and otherwise return #F.
POSP uses PROCEDURE as a predicate to compare OBJECT to each member
of list.
(Position a b) equals (posp equal? a b)
(Posv a b) equals (posp eqv? a b)
(Posq a b) equals (posp eq? a b)
(position '(bar) '((foo) (bar) (baz))) ==> 1
(posv 4 '(0 1 2 3 4 5 6)) ==> 4
(posq 'foo '(foo bar baz)) ==> 0
(posp (lambda (x y) (= x (car y)))
2
'((0 . a) (1 . b) (2 . c))) ==> 2
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