Set membership operators

Learn how to use and combine different set membership operators in APL

The table summarizes the set membership operators available in APL. These operators filter records based on whether a value matches any element in a specified set.

Name	Description	Case-sensitive
in	Returns true if the value equals any of the elements.	Yes
!in	Returns true if the value doesn’t equal any of the elements.	Yes
in~	Returns true if the value equals any of the elements.	No
!in~	Returns true if the value doesn’t equal any of the elements.	No