SetIntersection / List Layer

Compute the set intersection between two variable-length lists. Returns a list containing elements that exist in both lists. Similar to Python's set intersection operation or SQL's INTERSECT.

Mathematical definition: For sets A and B, the intersection A ∩ B is defined as: $A \cap B = {x ∣ x \in A and x \in B}$ In other words, elements that are in both A and B.

Example transformation:

left_list	right_list	intersection
[1, 2, 3, 4]	[2, 4, 5]	[2, 4]
[a, b, c]	[b, d]	[b]
[1, 1, 2, 3]	[1, 2]	[1, 2]
[x, y]	[]	[]
[1, null, 3]	[1, 2]	[1]

Properties:

Commutative: $A \cap B = B \cap A$
Associative: $(A \cap B) \cap C = A \cap (B \cap C)$
Identity: $A \cap U = A$ (where U is the universal set)
Null set: $A \cap \emptyset = \emptyset$

Common applications:

Finding common features between versions
Identifying shared permissions
Detecting overlapping categories
Finding matching elements
Computing common attributes
Analyzing shared characteristics

Note: Duplicates in input lists are removed (set semantics). Null values are ignored. Order of elements in result is not guaranteed. Lists can have different lengths.

Table

SelectLeft

column

The first list column (SelectLeft) for intersection. Examples:

User A permissions: [read, write, execute]
Product features: [f1, f2, f3]
Category tags: [electronics, computers, phones] Lists can have different lengths. Duplicates allowed but treated as single elements.

SelectRight

column

The second list column (SelectRight) for intersection. Examples:

User B permissions: [read, execute]
Required features: [f1, f3]
Search tags: [computers, software] Lists can have different lengths. Duplicates allowed but treated as single elements.

Name for the new column. If not provided, the system generates a unique name. If AsColumn matches an existing column, the existing column is replaced. The name should follow valid column naming conventions.