Add to List

Add to List

Type: list-add  ·  Package: Collections Activities v1.0.3  ·  Output: none

Adds an element to the end of a list. It is the activity to accumulate data: keep storing each result as you loop through something.

How it works

Appends item to the end of list, modifying it directly: any variable pointing to it sees the change. The list must exist (create it first with Create List). Repeated elements and null are allowed.

If the list has a specific type (for example, the List<string> returned by split(...)), the element must be of that type; lists created with Create List or newList() accept any value.

Required parameters

Parameter	Type	Default	Description
list	List	—	The list to add to.
item	object	—	The element to add.

Optional parameters

None.

Output

This activity does not return a value; it modifies the list in place.

Common errors

Message	Cause and fix
'list' must be a List, got ….	list is not a list (the message shows the type received, or null if the variable is empty). Create it first with Create List.
The value "…" is not of type "…" and cannot be used in this generic collection.	The list has a specific type and the element is of another one (.NET message). Convert the element, for example with str(...).

Example

Create List   → output: pending
For Each   items = invoices   itemVariable = invoice
 └─ activities:
      If   condition = str(invoice["Status"]) == "Pending"
       └─ then:
            Add to List   list = pending   item = invoice["Number"]

Log   message = "Pending invoices: " + join(pending, ", ")

Expression equivalent

listAdd(list, value) does the same in an expression.

Related activities

• Create List — create the list.
• Get List Item — read an element.
• List Count — count elements.