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Python sets are very much like mathematical sets, and support operations like set intersection and union. Python also features a frozenset class for immutable sets, see Collection types. Dictionaries (class dict) are mutable mappings tying keys and corresponding values. Python has special syntax to create dictionaries ({key: value})
A data structure known as a hash table.. In computer science, a data structure is a data organization and storage format that is usually chosen for efficient access to data. [1] [2] [3] More precisely, a data structure is a collection of data values, the relationships among them, and the functions or operations that can be applied to the data, [4] i.e., it is an algebraic structure about data.
Datalog is a database definition language, which combines a relational view of data, as in relational databases, with a logical view, as in logic programming. Relational databases use a relational calculus or relational algebra, with relational operations , such as union , intersection , set difference and cartesian product to specify queries ...
The ability to define control flow (structures) as abstractions instead of primitives. The ability to define potentially infinite data structures. This allows for more straightforward implementation of some algorithms. The ability to define partly-defined data structures where some elements are errors. This allows for rapid prototyping.
Each such rule can be read as an implication: … meaning "If each is true, then is true". Logic programs compute the set of facts that are implied by their rules. Many implementations of Datalog, Prolog, and related languages add procedural features such as Prolog's cut operator or extra-logical features such as a foreign function interface.
Declarative programming is often defined as any style of programming that is not imperative. A number of other common definitions attempt to define it by simply contrasting it with imperative programming. For example: A high-level program that describes what a computation should perform.
In logic, syntax is anything having to do with formal languages or formal systems without regard to any interpretation or meaning given to them. Syntax is concerned with the rules used for constructing, or transforming the symbols and words of a language, as contrasted with the semantics of a language which is concerned with its meaning.
In the spirit of functional programming, each state of an abstract data structure is a separate entity or value. In this view, each operation is modelled as a mathematical function with no side effects. Operations that modify the ADT are modeled as functions that take the old state as an argument and returns the new state as part of the result.