The LOOKUP function finds the row index of 'value' in @vector1 and returns the contents of value2 at that row index. If the area is longer than it is wide then the sense of the search is rotated. Alternatively a single array can be used.
If LOOKUP can't find @value it uses the next largest value less than value. The data must be sorted.
If @value is smaller than the first value it returns #N/A