Array Operations

Arrays can be used to store multiple pieces of information. Refer to Available Base Types for more information on arrays in Designer context in general.

Arrays of arrays are not supported by the Designer.

The following operations can be used to manipulate and access arrays:

Operation	Description
`[ ]`	The bracket operator can be used to get and set array elements.
append	Append elements to arrays.
apply	Apply an action script operations to array elements.
buildMap()	Build a map from an array.
concatArrays()	Concatenate the elements of one or more arrays to a target array.
count()	Count the number of elements in an array.
getMapEntries()	Get all map entries to an array.
join()	Concatenate all strings of an array of strings, and separate them by a separator.
reduce	Reduce array valued types to scalars.
select	Filter array items by evaluating a boolean expression for each array element using an SQL like syntax.
sort	Sort array elements in defined order.

All Any type operations listed on Any Type Operations also apply to arrays as all types derive from Any.

Creating Arrays

You can create arrays using the create statement (see action script example below):

CODE

create anArray;
append "Hello World!" to anArray;

Most of the time the xUML Runtime will create the array implicitly on appending the first item. There is one exception to this rule, though: Arrays that contain array elements having a complex type with multiplicity.

Let's assume you have an array of complex type ArrayElement and this complex type has a property subArray with multiplicity 0..*.

What you can do, if subArray is NULL:

CODE

//The reference subArray is changed to point to anotherArray.
set array1[0].subArray = anotherArray;

What you can't do, if subArray is NULL:

CODE

append "something" to array1[0].subArray;

In this case (get statement on the right side of a statement), the Runtime will throw a get error for array1[0].subArray.

Some Array How-tos

Find below a list of some useful code snippets in array context:

Task	Code Snippet	Descriptions
empty array	CODE `set array = select each from array where false;`	A new array is created containing all references to elements of array that correspond to the condition (which are none). The reference of array is changed to point to the new array. `array` is empty now. You can append items using the append Statement.
empty array	CODE `set array = NULL;`	The reference of array is changed to point to nowhere. This results in a non-existent array. You can append items using the append Statement, the array will implicitly be created, then.
copy all content from array1 to array2	CODE `set array2 = select each from array1 where true;`	A new array is created containing all references to elements of array1 that correspond to the condition (which are all). The reference array2 is changed to point to the new array. In the UML model you will now see two arrays array1 and array2 that contain the same element references. A change to `array1` itself will not change array2 (e.g. appending elements), but a change to an element of array1 will change that very same element in array2.
copy all content from array1 to array2	CODE `set array2 = array1.copy();`	A new array is created that contains a true deep copy of all elements of `array1`. The reference array2 is changed to point to the new array. In the UML model you will now see two arrays array1 and array2 that are completely independent. A change to array1 in any way will not change array2.
append all content from array1 to array2	CODE `set array2 = array2.concatArrays(array1)`	A new array is created containing all references to elements of array1 and array2. The reference array2 is changed to point to the new array. In the UML model you will now see an array array2 containing all element references of array1 and array2. A change to array1 itself will not change array2 (e.g. appending elements), but a change to an element of array1 will change that very same element in array2.

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