On 04/09/2023 23:55, JEFFRY KILLEN wrote:
It could also be seen:
null == 0
null(0) + null(0) == 0
JK
On Sep 4, 2023, at 3:51 PM, Ashley Sheridan <ash@xxxxxxxxxxxxxxxxxxxx> wrote:
On 04/09/2023 05:35, tyamahori wrote:
Dear PHP users.
I have questions about the behavior `null + null = 0`.
Since PHP4.3.0, `null + null` becomes `0`.
https://3v4l.org/YX3Od#veol
Form php-src,
https://github.com/php/php-src/blob/e2189e5f376092eeaeb4c06ff9b5918bfc016917/Zend/zend_operators.c#L325
It seems _zendi_try_convert_scalar_to_number converts null to 0.
Do you know who decided this behavior ?
Do you know how did this behavior come about?
Regards.
Kazuki
What you're looking at here is type coercian, or as PHP refers to it, type juggling.
You're using a non-numerica type as a number when you use the + operator. This has the effect of casting null first to an int, which results in your calculation becoming 0 + 0.
More details on PHPs type juggling can be found at https://www.php.net/manual/en/language.types.type-juggling.php
Thanks,
Ash
--
www.ashleysheridan.co.uk
Please try not to top post.
Technically, null == 0 is true, but only because you're using loose
typed comparisons, which themselves then fall back to the type
comparison table
(https://www.php.net/manual/en/language.operators.comparison.php#language.operators.comparison.types
), which attempts to convert it to an empty string or a zero, which is
why null == "" as well.
Thanks,
Ash
--
www.ashleysheridan.co.uk
