Itemwise

Itemwise is an adjective used to describe operations or analyses that are performed on each item within a collection independently, rather than aggregating or operating on the collection as a whole. The term derives from item meaning an individual element and the suffix -wise indicating per-item consideration. In practice, itemwise operations are common where per-record or per-element processing is required.

In computing and data processing, itemwise commonly refers to elementwise or per-item transformations. For example, applying a function to each element of a list or array executes itemwise. In data pipelines, itemwise normalization or scaling adjusts each record or item separately, as opposed to aggregating across the dataset. In programming, many languages support itemwise operations through map functions or vectorized operations; while itemwise is used occasionally, elementwise or per-element is the more standard term.

In other domains, itemwise can describe procedures performed for each distinct item in inventory, orders, or a catalog. Itemwise pricing or itemwise packaging means policies that apply at the level of individual items rather than by batch or category.

See also: elementwise, per-item, per-element, maps and vectorization.

Notes: The term is not as widely standardized as elementwise, and its exact meaning can vary by field. In mathematical contexts, Hadamard (elementwise) product is often the preferred terminology.