#50738 [Opn->Csd]: Unclear documentation in numerical string comparison

ID: 50738 Updated by: rquadling@php.net Reported By: I dot F dot A dot C dot Fokkema at LUMC dot nl -Status: Open +Status: Closed Bug Type: Documentation problem Operating System: All PHP Version: Irrelevant New Comment: This bug has been fixed in the documentation's XML sources. Since the online and downloadable versions of the documentation need some time to get updated, we would like to ask you to be a bit patient. Thank you for the report, and for helping us make our documentation better. Previous Comments: ------------------------------------------------------------------------ [2010-01-13 13:25:31] svn@php.net Automatic comment from SVN on behalf of rquadling Revision: http://svn.php.net/viewvc/?view=revision&revision=293501 Log: Fix#50738 - Type juggling is excluded from identical and not identical comparisons. "If you compare an integer with a string, excluding the identical (===) and not identical (!===) operators, the string is ..." ------------------------------------------------------------------------ [2010-01-13 11:14:50] rquadling@php.net How about ... "If you compare an integer value with a string value (as opposed to comparisons including type; === and !===), ..." ------------------------------------------------------------------------ [2010-01-13 11:07:06] I dot F dot A dot C dot Fokkema at LUMC dot nl Description: ------------ Hi guys, After someone filed bug report #23110, the documentation was greatly improved to emphasize pitfalls when comparing numerical strings. However, I want to suggest an addition because in my point of view it's not clear enough. == and === compare numerical strings differently: echo (1 == "1e0") // Returns true, as documented echo (1 === "1e0") // Returns false as expected, because the types are different echo ("1" == "1e0") // Returns true, as documented echo ("1" === "1e0") // Returns false, but the documentation says otherwise The documentation at http://www.php.net/manual/en/language.operators.comparison.php currently reads: "If you compare an integer with a string, the string is converted to a number. If you compare two numerical strings, they are compared as integers. These rules also apply to the switch statement." - this was added after bug report #23110. So according to this, ("1" === "1e0") should return true; the converted numbers are equal and they're of the same type. However, it returns false because the number conversion described in the manual does not happen when using === or !==, but that is not documented. More people have issues with this, as can be seen looking through the comments on the aforementioned manual page. Thus, I would like to suggest an addition at the end: "(...) These rules also apply to the switch statement, but they do not apply when using the operators === or !==, in which case there is no type conversion used." Or a similar explanation of course. Thank you all for your great work! ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=50738&edit=1