List Contains

List Contains

Type: list-contains  ·  Package: Collections Activities v1.0.3  ·  Output: bool

Checks whether a list contains an element and returns true/false. Useful to avoid duplicates or validate membership.

How it works

Looks for item in list, comparing each element by exact equality, type included:

• Text is case-sensitive ("ana" is not "Ana").
• A number is not equal to its text (5 is not "5"), and numbers of different types don’t match either (integer 5 is not decimal 5.0). If the list comes from another source, convert the value you look for to the same type first, for example with str(...).

It does not modify the list.

Required parameters

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

Optional parameters

None.

Output

Returns a bool: true if any element equals item, false otherwise (also for an empty list).

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).

Example

Avoid adding a repeated element:

List Contains   list = processed   item = id   → output: alreadyThere
If   condition = !alreadyThere
 └─ then:
      Add to List   list = processed   item = id

Expression equivalent

list.Contains(value) gives the same result in an expression.

Related activities

• Add to List — add the element if it is not there.
• List Count — count elements.