Updated on December 24 2019 • Martin Shishkov

In computing, an idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item by ID from a set can be considered an idempotent operation on the set.

In mathematics, an idempotent operation is one where f(f(x)) = f(x). For example, the abs() function is idempotent because abs(abs(x)) = abs(x) for all x.