11.09.2021, 15:19 | #1 |
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d365technext: Definition of List, Set, Container, and Map
Источник: https://d365technext.blogspot.com/20...r-and-map.html
============== Difference between List, Set, Container, and Map Containers: Containers are dynamic and have no limits. They can contain elements of almost all data types: boolean, integer, real, date, string, container, arrays, tables, and extended data types. However, objects may not be stored in containers. Containers in AX are used very often. It’s easy to work with them. But… data in containers are stored sequentially and thus retrieved sequentially. This means that containers provide slower data access if you are working with _large numbers_ of records. In case of large numbers of records use temporary tables. List: Lists are structures that may contain any number of elements that are accessed sequentially. Lists may contain values of any X++ type. All the values in the list must be of __the same__(this is the main difference between lists and containers) type, given in the creation of the list. The implementation of lists is such that the traversal of the list elements is __very fast. Take a look for example at the class Dialog addControl() method. Their controls are stored in ctrls List. Map: A map is a data type that associates one (key) value with another value [An analog – a small table in memory with two fields: Keys, Values]. Both the key and value values may be of any valid X++ type, including objects. The types of the key and the value are given in the declaration of the map. The implementation of maps is such that access to the values is _very fast_. Don’t confuse map X++ types with Map objects in AOT, which are used for mapping tables with similar structures of fields – Set: The functionality of Sets is similar to the list. A Set is just an unordered list of items, while a list of items held by a Map are indexed via a key. Take look at \Classes\sysLabel\LabelModuleId(). Источник: https://d365technext.blogspot.com/20...r-and-map.html
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