oppslagstabell

An oppslagstabell, often translated as a lookup table or reference table, is a data structure used in computing and mathematics to store a set of predefined values. These values are typically organized in a way that allows for quick retrieval based on a specific key or index. Instead of performing a complex calculation or searching through a large dataset each time a value is needed, the oppslagstabell provides a direct mapping from an input to its corresponding output.

The primary advantage of using an oppslagstabell is its efficiency. By pre-calculating or pre-determining the values, subsequent lookups can be very fast, often approaching constant time complexity depending on the implementation. This makes them ideal for situations where a particular set of results is frequently accessed. For example, in computer graphics, a color lookup table (CLUT) maps pixel values to specific colors. In programming, an array can serve as a simple oppslagstabell where the index is the key. More complex implementations might use hash tables or dictionaries.

Oppslagstabeller can be static, meaning their contents are fixed once created, or dynamic, where values can be added, removed, or modified. The size of an oppslagstabell is determined by the number of entries it contains. While efficient for retrieval, oppslagstabeller can consume memory, and the cost of building or updating them needs to be considered. They are a fundamental concept in data management and algorithm design.