#48484 [Opn]: array_product(array()) returns 0 instead of 1.

ID: 48484 User updated by: zhalassy at loginet dot hu Reported By: zhalassy at loginet dot hu Status: Open Bug Type: Math related Operating System: Any PHP Version: 5.2.9 New Comment: http://en.wikipedia.org/wiki/Identity_element An identity with respect to addition is called an additive identity (often denoted as 0) and an identity with respect to multiplication is called a multiplicative identity (often denoted as 1). The distinction is used most often for sets that support both binary operations, such as rings. The multiplicative identity is often called the unit [...] http://en.wikipedia.org/wiki/Unital In mathematics, an algebra is unital (some authors say unitary) if it contains a multiplicative identity element (or unit), i.e. an element 1 with the property 1x = x1 = x for all elements x of the algebra. http://en.wikipedia.org/wiki/Empty_product Previous Comments: ------------------------------------------------------------------------ [2009-06-06 11:22:13] zhalassy at loginet dot hu Description: ------------ array_product(array()) returns 0 instead of 1. Empty product is 1 (hence "1" is neutral in multiplication) in mathematics. Example: array_product(array(1,2)) * array_product(array(3,4)) === /* should be */ array_product(array()) * array_product(array(1,2,3,4)); example implementation: function array_product($array){ $product = 1; foreach($array as $element) $product *= $element; return $product; } Reproduce code: --------------- echo product_array(array()); Expected result: ---------------- It should return 1. Actual result: -------------- It returns 0. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=48484&edit=1