# EXAMPLE - ARRAYLEN and ARRAYELEMENTAT Functions

This example illustrates how to return n-based number of elements in an array.

Functions:

Item

Description

ARRAYLEN Function

Computes the number of elements in the arrays in the specified column, array literal, or function that returns an array.

ARRAYELEMENTAT Function

Computes the 0-based index value for an array element in the specified column, array literal, or function that returns an array.

ARRAYSORT Function

Sorts array values in the specified column, array literal, or function that returns an array in ascending or descending order.

Source:

Here are some student test scores. Individual scores are stored in the Scores column. You want to:

1. Flag the students who have not taken four tests.

2. Compute the range in scores for each student.

LastName

FirstName

Scores

Allen

Amanda

[79, 83,87,81]

Bell

Bobby

[85, 92, 94, 98]

Charles

Cameron

[88,81,85]

Dudley

Danny

[82,88,81,77]

Ellis

Evan

[91,93,87,93]

Transformation:

First, you want to flag the students who did not take all four tests:

 Transformation Name New formula Single row formula IF(ARRAYLEN(Scores) < 4,"incomplete","") 'Error'

This test flags Cameron Charles only.

The following transform sorts the array values in highest to lowest score:

 Transformation Name Edit column with formula Scores ARRAYSORT(Scores, 'descending')

The following transforms extracts the first (highest) and last (lowest) value in each student's test scores, provided that they took four tests:

 Transformation Name New formula Single row formula ARRAYELEMENTAT(Scores,0) 'highestScore'
 Transformation Name New formula Single row formula ARRAYELEMENTAT(Scores,3) 'lowestScore'

Dica

You could also generate the Error column when the Scores4 column contains a null value. If no value exists in the array for the ARRAYELEMENTAT function, a null value is returned, which would indicate in this case an insufficient number of elements (test scores).

You can now track change in test scores:

 Transformation Name New formula Single row formula SUBTRACT(highestScore,lowestScore) 'Score_range'

Results:

LastName

FirstName

Scores

Error

lowestScore

highestScore

Score_range

Allen

Amanda

[87,83,81,79]

79

87

8

Bell

Bobby

[98,94,92,85]

85

98

13

Charles

Cameron

[88,85,81]

incomplete

88

Dudley

Danny

[88,82,81,77]

77

88

11

Ellis

Evan

[93,93,91,87]

87

93

6