- vector-index pred? vec_1 vec_2 ···procedure
Finds & returns the index of the first elements in vec_1 vec_2 ··· that satisfy pred?. If no matching element is found by the end of the shortest vector, #f is returned.
Examples:
(vector-index even? '#(3 1 4 1 5 9)) ;=> 2
(vector-index < '#(3 1 4 1 5 9 2 5 6) '#(2 7 1 8 2)) ;=> 1
(vector-index = '#(3 1 4 1 5 9 2 5 6) '#(2 7 1 8 2)) ;=> #f