fluffos/docs/stdlib/arrays/reduce.md

title
stdlib / reduce

reduce

NAME

reduce - Inspired by JavaScript's Array.reduce()

SYNOPSIS

varargs mixed reduce( mixed *elements, mixed fun, mixed initial, mixed args... )

DESCRIPTION

Iterate over an <arr>, passing each element to a function <fun>.
The function should return a new value which becomes the new
total. Function <fun> can be a function or a string. If it is a
string, it will call the named function in the calling object
(via previous_object()).

Parameters:

(required) mixed *elements - the array to be worked upon
(required) function | string fun - the reducer function
(optional) mixed initial - the initial value to set
(optional) mixed args... - additional arguments to pass to <fun>

The following are passed as arguments to <fun> at every iteration.

(required) mixed total - The <initial> value, or the previously returned value of the function
(required) mixed currentValue - The value of the current element
(optional) int currentIndex - The array index of the current element
(optional) mixed *arr - The array the current element belongs to
(optional) mixed args... - Additional arguments

The function should return what will become the new total.

EXAMPLE

reduce( ({ 1, 2, 3, 4 }), function( int total, int current ) {
   return total + current ;
}) ;
//Result: 10

reduce( ({ 1, 2, 3, 4 }), function( int total, int current ) {
   return total + current ;
}, 10) ;
//Result: 20

result7 = reduce( explode("FluffOS", ""), function( int total, int current, int idx, int* arr ) {
    return total + arr[sizeof(arr) - idx - 1] ;
}, "") ;
//Result: "SOffulF"

reduce( ({ "north", "south", "east", "west" }), function( string total, string current, int idx, string* arr, string conjunction ) {
    if( idx == 0 ) return current ;

    total += ", " ;

    if( idx == sizeof( arr ) - 1 ) total += conjunction + " " ;

    return total + current ;
}, "", "or") ;
//Result: "north, south, east, or west"