find

(find item sequence &key test key)

Returns the first element of sequence that matches item, or nil if no element matches. The comparison is eql by default; the optional :test keyword takes a function designator to use a different comparison, and the optional :key keyword takes a selector function applied to each element before the comparison (the returned element is the original one, not the keyed value). The sequence may be a list or a string; the elements of a string are characters. Unlike member, which returns the matching tail, find returns the element itself. Use position to obtain the index instead.