Arrays

What are arrays?

Like variables, arrays are used to represent data in a task that may be different each time a task runs. But unlike standard variables, arrays can contain multiple rows and optionally multiple columns. You may want to think of an array as nothing more than a list, such as a shopping list, to-do list, birthday list, etc. All items in an array, like the items in a list, have a position somewhere between first and last. Items are numbered from lowest to highest in arrays, therefore, they are accessed by number. For example, to retrieve the element in Row 2, Column 10, the following expression would be entered:

%arrayName(2,10)%

One & two dimensional arrays

An array can be used to store a list of data read from a text file or other system containing customer data. For instance, if there are 10 customers, the array would need to have 10 rows. If the data consisted of first name, last name, and company name it would need 3 columns and would need to be a two dimensional array. An array can also be a simple list of text or numeric values (for example, multiple rows of data, only one column), this is called a one dimensional array.

An array with only one dimension is linear. In other words, it contains a list of data that can be referenced by a number. For example if my one dimensional array named myArray had 3 values, then the syntax would be:

MyArray(1) = value1
MyArray(2) = value2
MyArray(3) = value3

In a two dimensional array, you have both rows and columns, such as a spreadsheet. You would then need to reference a cell by row and column, like the expression below which references row 1, column 5.

%MyArray(1,5)%

Creating & setting arrays

The Array action contains individual activities that allow you to create or modify an array. To create an array, use the Array - Create activity. In the properties of this activity, you give your array a name, choose whether you want your array to be a one , two or three dimensional array and optionally, set its values. After creating an array, you can set its values in any task step using the Array - Set activity or you can re-size an array using the Array - Resize activity.

Examples

Example 1

This is a simple task that associates each array with a color.

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<AMARRAY NAME="MyArray" TYPE="TEXT" ROWS="3" />
<AMVARIABLE ACTIVITY="set" VARIABLENAME="MyArray(1)" VALUE="Red" />
<AMVARIABLE ACTIVITY="set" VARIABLENAME="MyArray(2)" VALUE="Blue" />
<AMVARIABLE ACTIVITY="set" VARIABLENAME="MyArray(3)" VALUE="Green" />
<AMSHOWDIALOG>%MyArray(1)%; %MyArray(2)%; %MyArray(3)%</AMSHOWDIALOG>

Example 2

This is a more complex task that uses functions and performs loops (requires a folder called c:\test\ with a few files in it).

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<AMVARIABLE NAME="thefilename" />
<AMVARIABLE NAME="counter" />
<AMARRAY NAME="MyArray" ROWS="%FileCount('c:\test\')%" TYPE="text" />
<AMLOOP ACTIVITY="folder" FOLDER="c:\test\" RESULTVARIABLE="thefilename" />
<AMLOOP FROM="1" TO="%UBound(myarray, 1)%" RESULTVARIABLE="counter" />