System.Reduce

Declaration

function Reduce(Values: System.Struct, Reducer: function, Initial = System.Null) = \built-in\

Description

The Reduce function in the System package reduces an existing structure (array or record) to a single value.

The second parameter is a function with two parameters. When the function is called, System.Length(Values) iterations are done through the structure and the accumulator plus value for each element/field is passed as argument to Reducer. The reducer function shall return a value that replaces the whole structure that is then either passed to the next iteration or returned as function result.

Remarks

• The function result is the result from the final call of Reducer.
• Reducer is called with the accumulator (or Initial parameter in the first run) as first and with the current element/field value as second argument.
• If the length of Values is zero, Reducer is never called and Initial is returned.
• If Reducer demands more or less arguments than 2, an exception is raised.

See also

• System.Creep
• System.Map
• System.Filter
• System.Flatten