The 1D-array is a special type of
array that represents a one-dimensional ordered sequence of scalar (i.e. non-array) data.
See also the
array for an example of a 1D-array of integers.

In Excel, it is represented by contiguous cells that may extend in either the horizontal or vertical direction.
The orientation of the cells is irrelevant.
For example, if a function expects as input a 1D-array, it makes no difference if that input is supplied as a single row or as a single column.
A cell containing the text [end] is itself not part of the array and indicates that the last array element is the preceding cell.
If the context permits it, one or more cells may be left blank, in which case they specify undefined elements that are interpreted in a context-dependent way.
For example, an empty cell in a context where a swap rate is expected usually means the at-the-money rate.
An empty array is an array with a zero number of elements and can be specified by a single cell containing the text [end]