Collections Activities

Version: 1.0.3  ·  ID: zoan-packages-collections  ·  Author: Zoan Software

The Collections package creates and manipulates the two most commonly used collection types: lists (sequences of elements) and dictionaries (key→value pairs). It is used to accumulate results, keep records, group related data or configure options.

Before you start

It is useful to know these two data types: a list is an ordered sequence (["Ana", "Luis"]); a dictionary associates keys with values ({ "city": "Bogotá", "age": 30 }). List indexes start at 0.

Activity or expression: the two forms

Almost everything these activities do also has a direct equivalent in an expression. For example:

Goal	Activity	Equivalent expression
Count elements	List Count	count(list) or list.Count
Element by index	Get List Item	list[0]
Does it contain?	List Contains	list.Contains(value)
Value of a key	Get Dictionary Value	d["key"] (or dictGet(d, "key"), which gives null instead of failing when the key does not exist)
Add to list	Add to List	listAdd(list, value)

Which one to use? The activities make the flow more explicit and visual (useful for those just starting out). The expressions are shorter and more comfortable when you are already inside another formula. Both are correct — choose according to whether you prefer clarity or concision. See Expressions › Collections.

Where the result goes

Activities that return a result (create, count, get, check) deliver it through the activity’s output field, like every other activity: you pick there the variable that receives it (→ output: variable in the examples). Activities that modify a collection (add, set, remove, clear) change it in place and return nothing: any variable pointing to that list or dictionary sees the change.

Activities

Lists

Activity	Type	Output	What it does
Create List	list-create	List	Create a list, empty or with initial items
Add to List	list-add	—	Add an item
Get List Item	list-get	object	Element by index
List Count	list-count	int	Number of elements
List Contains	list-contains	bool	Does it contain an element?
Remove from List	list-remove-at	—	Delete by index
Clear List	list-clear	—	Empty the list

Dictionaries

Activity	Type	Output	What it does
Create Dictionary	dict-create	Dictionary	Create a dictionary, empty or with initial pairs
Set Dictionary Value	dict-set	—	Assign/update a key
Get Dictionary Value	dict-get	object	Value of a key
Dictionary Contains Key	dict-contains-key	bool	Does the key exist?
Dictionary Count	dict-count	int	Number of pairs
Get Dictionary Keys	dict-keys	List	All the keys
Remove Dictionary Key	dict-remove	—	Delete a key

Next steps

• Create List / Create Dictionary — create a collection.
• Data Types › Collections — their properties and methods.
• Expressions › Collections — the alternative in a single line.