Doc #76875 [Com]: It is not clear what 'uncomparable' means

Edit report at https://bugs.php.net/bug.php?id=76875&edit=1 ID: 76875 Comment by: a at b dot c dot de Reported by: manabu dot matsui at gmail dot com Summary: It is not clear what 'uncomparable' means Status: Open Type: Documentation Problem Package: Documentation problem PHP Version: Irrelevant Block user comment: N Private report: N New Comment: "Uncomparable" means "cannot be compared". That means there is no well-ordering on arbitrary arrays that allows such comparisons to be made in any sensible fashion (how do _you_ think $x and $y should be ordered?). ['a' => 1] < ['b' => 2], for one, evaluates to FALSE because ['a' => 1] is not less than ['b' => 2]. (The operator is defined as returning TRUE if its left argument is less than its right. This is not the case here.) In the same way, ['a' => 1] > ['b' => 2] is FALSE because ['a' => 1] is not greater than ['b' => 2] and ['a' => 1] == ['b' => 2] is FALSE because ['a' => 1] is not equal to ['b' => 2]. Previous Comments: ------------------------------------------------------------------------ [2018-09-13 01:11:19] manabu dot matsui at gmail dot com Description: ------------ --- From manual page: http://www.php.net/language.operators.comparison --- In table 'Comparison with Various Types', it is said that 'if key from operand 1 is not found in operand 2 then arrays are uncomparable', and according to Example 2, the standard_array_compare function returns null in that case. When I actually tried it, each operator returned the following value. <?php $x = ['a' => 1]; $y = ['b' => 2]; var_dump($x < $y); # false var_dump($x <= $y); # false var_dump($x > $y); # false var_dump($x >= $y); # false var_dump($x <=> $y); # 1 ?> I can not explain this result from the manual description. I think it would be better to explain more clearly. What is the meaning of 'uncomparable'? For example, the following can be considered * If $x and $y are uncomparable, $x < $y, $x <= $y, $x > $y, $x >=$y are all false, and $x <=> $y is 1. * It returns some kind of value, but it is indeterminate what the value is. (The above example happened to be so, in different situations it could be different results) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=76875&edit=1