addif

Addif is a term used in software development to describe a conditional addition: inserting an element into a collection only when a specified predicate evaluates to true. It is not a formal language feature but a common pattern employed across languages and libraries.

Typical implementations appear as a function or method that accepts a container, an item, and a predicate. Depending on the design, the operation may mutate the original container or return a new collection that includes the item if the predicate passes.

Examples (illustrative): In Python, addif could be implemented as def addif(container, item, pred): return container + [item] if pred(item) else container. In JavaScript: function addIf(arr, item, pred) { return pred(item) ? arr.concat(item) : arr; } In functional style, you might map or filter to achieve similar results.

Design considerations include immutability versus mutability, handling of duplicates, and predicate side effects. Some libraries expose addif as a guard-free helper, while others incorporate it into data pipelines as a single step.

See also: conditional append, guard clauses, filter, map.