Section about computable function.
A function is a callable unit that may be called:
- a procedure,
- a subrontine
- a routine,
- a method (belong to an object)
- a subprogram
- a task
- a map
- a mapping
- a transformation
- a macro
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.
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.
Function property. See (Function|Operator) - Algebraic (Laws|properties) - Axioms
The concept of function is defined as a special kind of binary relation.
input -> Rule -> Output
A function declaration has generally:
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.
User Defined Functions (UDF)
Time serie function
Aggregate functions return a single value, calculated from values in a column.
Did they return always the same result ? deterministic properties