External module "utils/map-reduce-right/docs/types/index.d"

Export assignment mapReduceRight

• mapReduceRight(arr: ndarray, initial: any, mapper: Mapper, reducer: Reducer, thisArg?: any): any
• mapReduceRight(arr: Collection, initial: any, mapper: ArrayMapper, reducer: ArrayReducer, thisArg?: any): any

• Performs a map-reduce operation for each element in an array while iterating from right to left and returns the accumulated result.

  Notes

  • The mapping function is provided four arguments:

    • value: array element.
    • index: element index.
    • arr: input array.

  • The reducing function is provided four arguments:

    • accumulator: accumulated value.
    • value: result after applying a mapping function to the current array element.
    • index: element index.
    • arr: input array.

  • If provided an empty array, the function returns the initial value.

  Parameters

  • arr: ndarray

    input array

  • initial: any

    initial value

  • mapper: Mapper

    mapping function

  • reducer: Reducer

    reducing function

  • Optional thisArg: any

    reducing function execution context

  Returns any

  accumulated result

  Example

  var naryFunction = require( `@stdlib/utils/nary-function` );
  var abs = require( `@stdlib/math/base/special/abs` );
  var add = require( `@stdlib/math/base/ops/add` );
  var array = require( `@stdlib/ndarray/array` );
  
  var opts = {
      'dtype': 'generic'
  };
  var arr = array( [ [ -1, -2, -3 ], [ -4, -5, -6 ] ], opts );
  
  var out = mapReduceRight( arr, 0, naryFunction( abs, 2 ), naryFunction( add, 2 ) );
  // returns 21

• Performs a map-reduce operation for each element in an array while iterating from right to left and returns the accumulated result.

  Notes

  • The mapping function is provided four arguments:

    • value: array element.
    • index: element index.
    • arr: input array.

  • The reducing function is provided four arguments:

    • accumulator: accumulated value.
    • value: result after applying a mapping function to the current array element.
    • index: element index.
    • arr: input array.

  • If provided an empty array, the function returns the initial value.

  Parameters

  • arr: Collection

    input array

  • initial: any

    initial value

  • mapper: ArrayMapper

    mapping function

  • reducer: ArrayReducer

    reducing function

  • Optional thisArg: any

    reducing function execution context

  Returns any

  accumulated result

  Example

  function square( value ) {
      return value * value;
  }
  
  function sum( acc, value ) {
      return acc + value;
  }
  
  var arr = [ 1, 2, 3, 4 ];
  
  var out = mapReduceRight( arr, 0, square, sum );
  // returns 30