remove

(remove item sequence &key test key)

Returns a new sequence containing the elements of sequence with every element matching item omitted. 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 kept elements are the original ones). The sequence may be a list or a string; a string yields a new string. The original sequence is not modified; use delete for the destructive version (lists only).