AGB 260:
Agribusiness
Information
Technology
Arrays and Array Formulas
Useful Chapters in the Textbook
Regarding this Lecture

Chapter 17

Chapter 18
Arrays

An array is a collection of items
which can easily be represented as
cells in Excel spreadsheet.

Arrays in Excel can be one or two
dimensional which correspond to
the rows and columns of the
worksheet.

A one dimensional array can either
be one column or one row.
Arrays Cont.

A two dimensional array must have
both rows and columns.

An example of a one dimensional row
array:

{1,2,3,4,5}

Put this in a cell with an equal sign at the
beginning, highlight 5 cells in a single row,
press F2 and then CTRL-Shift-Enter
Arrays Cont.

An example of a one dimensional
column array:
 {1;2;3;4;5}

An example of a 3x2 two
dimensional array:
 {1,2;3,4;5,6}
Single-Cell Array Formulas
 Single-cell
array formulas
 These
formulas give a result in
one cell, e.g.,
={Sum(A1:A4*B1:B4)}.

When entering an array formula,
you must activate the cell and press
Ctrl+Shift+Enter
Single-Cell Array Formulas
Cont.

Suppose you have the names Bob,
Sean, and Stuart in cells A1:A3

If we want to calculate the average
length of individuals’ names, we
can do it in a single formula using
the idea of an array

=AVERAGE(LEN(A1:A3))
Multi-Cell Array Formulas
 Multi-cell
array formulas
 These
formulas give a result that
spans multiple cells.
 In
these formulas, you need to
select the cells for where the
results will be and press F2 to
select the cells.
Transposing an Array

A useful array formula is the
Transpose function.

This function will take a column
array and make it a row array, a
row array into a column array, and
it will transpose a matrix array.
Frequency Function

The frequency() function calculates
the number of times a value occurs
in an array, i.e., it helps you create
a histogram.

It has two main arguments:
 The
data_array argument is the array
of values your interested in
 The
Bins_array is the array that has
the numbers to be tallied.
Linest Function

The Linest() function returns the
results of doing a linear regression
on a column array of known Y’s
regressed against an array of known
X’s.

Linear regression is based on the
concept Y = mx + b
Linest Function Cont.

There are four arguments to the function:

Known_y’s – this is the set of numbers for the
dependent variable

Known_x’s – this is the set of numbers for the
independent variable(s)

Const – If you set this to True, it will estimate a
nonzero intercept b; false implies set b to zero

Stats – True gives you a set of regression
statistics, while false returns no statistics
Matrix Functions

Excel has three useful matrix
functions:
 Mmult()
which does matrix
multiplication of two arrays
 Mdeterm()
which gives you the
determinant of a square matrix
 Minverse()
which gives the inverse of a
square matrix
Matrix Functions Cont.

The functions can be useful when doing
matrix algebra, i.e., solving a set of
linear equations, but they can have
rounding issues

For example:

x+y= 80

x-y=20