History of Idiom 28 > diff from v30 to v31
Edit summary for version 31 :
Restored version 29
Restored version 29
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Version 30
2016-02-18, 16:57:58
Version 31
2016-02-18, 17:21:46
Idiom #28 Sort by a property
Sort elements of array-like collection items in ascending order of x.p, where p is a field of type Item of the objects in items.
Idiom #28 Sort by a property
Sort elements of array-like collection items in ascending order of x.p, where p is a field of type Item of the objects in items.
Code
class Item { public $p; public function __construct($p) { $this->p = $p; } } function cmp($a, $b) { if ($a->p == $b->p) { return 0; } return ($a->p < $b->p) ? -1 : 1; } $items[] = new Item(5.0); $items[] = new Item(3.0); $items[] = new Item(-1.0); $items[] = new Item(2.5); usort($items, "cmp"); // sort itemsay of Items using `cmp` function foreach ($items as $x) { echo "{$x->p}\n"; }
Comments bubble
Classic use of usort with a custom function for sorting objects by property.
Imports
with Ada.Containers.Vectors; use Ada.Containers;
Code
declare function Compare_Function (Left, Right : Item) return Boolean is (Left.P < Right.P); package Item_Vector_Sorting is new Item_Vectors.Generic_Sorting (Compare_Function); use Item_Vector_Sorting; begin Sort (Items); end;