Sequenced arrays that are not in the correct sequence

When the data is not in the correct sequence for a sequenced array, the %LOOKUPxx built-in functions and the LOOKUP operation code may find different values. The %LOOKUPxx built-in functions may not find a data value even if it is present in the array.

Since a binary search is used by the %LOOKUPxx built-in functions for a sequenced array, and the correct function of a binary search depends on the data being in order, the search may only look at a few elements of the array. When the array is out of order, the result of a binary search is unpredictable.

Note: When the LOOKUP operation code is used to find an exact match in a sequenced array, the search starts from the specified element and continues one element at a time until either the value is found or the last element of the array is reached.