Je was op zoek naar: callback (Koreaans - Slovaaks)

an interesting use of this function is to construct an array of arrays, which can be easily performed by using null as the name of the callback function
horeuvedený program vypíše:

array_filter() returns an array containing all the elements of input filtered according a callback function. if the input is an associative array the keys are preserved.
ak je vstup asociatívne pole, kľúče sa uchovajú.

usually when using two or more arrays, they should be of equal length because the callback function is applied in parallel to the corresponding elements. if the arrays are of unequal length, the shortest one will be extended with empty elements.
zaujímavé využitie tejto funkcie je vybudovanie poľa polí, ktoré sa dá jednoducho vytvoriť použitím null ako názvu spätného volania funkcie.

array_map() returns an array containing all the elements of arr1 after applying the callback function to each one. the number of parameters that the callback function accepts should match the number of arrays passed to the array_map()
počet parametrov, ktoré spätné volanie funkcie akceptuje, by sa mal zhodovať s počtom polí odoslaných funkcii array_map()