unverändertAlle

UnverändertAlle is a term used in German-language discussions of data processing and programming to denote a property of an operation that does not modify any element of the input when applied to all elements. The word combines unverändert (unchanged) with Alle (all), reflecting the idea that every element remains the same after the operation.

In practice, unverändertAlle characterizes non-mutating or identity-like transformations, in contrast to operations that mutate data in place or produce altered elements. The concept is closely related to the identity function and to referential transparency in functional programming, where an expression yields the same result for the same inputs and has no side effects.

Examples include the identity map f(x) = x applied to each element of a collection, or a pure validation pass that reads data without writing changes. Such operations are non-destructive and preserve content, and they can preserve reference relationships in certain programming models. The property is relevant in areas such as data preservation, auditing, and scenarios where a pass must not alter the dataset.

In instructional texts, unverändertAlle is sometimes used as a heuristic for explaining when a tool or function is safe to run without modifying the data. It is not a standard formal term across all communities, but it serves as a clear, intuitive label in German-language explanations of non-mutating operations.

See also: identity function, referential transparency, non-destructive modification, immutability.