(Function | Operator | Map | Mapping | Transformation | Method | Rule)
Table of Contents
1 - About
A function is a reusable block (section|chunk) of code written that:
- accepts arguments as input,
- performs a specific task,
- and returns some other information as output.
A function is also known as:
A function that belong to an object is called a methods
Catalog and type of function that you can meet in any development language.
The clarity of examples, and the software’s decipherability and debuggability in the real world, are likely far more important. Form must communicate function. Mike Bostocks
Function property. See (Function|Operator) - Algebraic (Laws|properties) - Axioms
The concept of function is defined as a special kind of binary relation.
2 - Articles Related
3 - Syntax
input -> Rule -> Output
4 - Declaration and Execution
A function declaration has generally:
- a name,
- a list of parameters,
- an optional list of results,
- and the function body, which contains the statements that define what the function does.
Execution of the function begins with the first statement and continues until it encounters a return statement or reaches the end of a function that has no results. Control and any results are then returned to the caller.
5 - Parallel
6 - Type
6.1 - User Defined Functions (UDF)
6.2 - Analytics Function
6.3 - Time serie function
6.4 - Aggregate functions
Aggregate functions return a single value, calculated from values in a column.
6.5 - Scalar functions
6.6 - Deterministic function
Did they return always the same result ? deterministic properties