An element of a vector is accessed by specifying the vector and the index of the desired element.
(vector-ref vector i)
accesses the ith element of vector. i must be in the range 0
to k - 1, where k is the length of the vector.
(vector-set! vector i obj)
sets the ith element of vector to be obj.
> (define v1 '#(tom dick harry)) v1> (vector-ref v1 1) dick
> (vector-set! v1 1 'jane) #(tom jane harry)
> (vector-ref v1 1) jane