Req #71239 [NEW]: Language construct for array_key_exists() (performance)

From: andreas at dqxtech dot net Operating system: PHP version: 7.0.2RC1 Package: Arrays related Bug Type: Feature/Change Request Bug description:Language construct for array_key_exists() (performance) Description: ------------ There are places on the web telling me that array_key_exists($k, $a) is slower than isset($a[$k]). https://startpage.com/do/search?query=php+performance+isset+vs+array_key_exists&cat=web&pl=chrome&language=english Tests with PHP 5.5.9 confirm this, it seems that array_key_exists() uses almost 4x the time of isset(). On the other hand: Semantically, array_key_exists() is preferable over isset(). If you already know that $a is an array and not null, and that $k is a valid array key, then you don't want to have this tested again. You want TRUE or FALSE if the variables are set, and a warning (and FALSE, I guess) otherwise. This allows the IDE to warn you if you test a variable that is possibly undefined, or possibly not an array. With isset(), the IDE will keep silent, which can lead to hidden bugs. In theory, array_key_exists() should be faster than isset(), because there are fewer cases to consider.. but it is not, because one is a function and the other a "language construct". Aside of that, there is of course the difference of how NULL values are handled.. In fact, in an ideal world, there would be two versions of array_key_exists(). Both with the performance of a language construct. But with a different behavior for NULL values. -- Edit bug report at https://bugs.php.net/bug.php?id=71239&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=71239&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=71239&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=71239&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=71239&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=71239&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=71239&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=71239&r=needscript Try newer version: https://bugs.php.net/fix.php?id=71239&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=71239&r=support Expected behavior: https://bugs.php.net/fix.php?id=71239&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=71239&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=71239&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=71239&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=71239&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=71239&r=dst IIS Stability: https://bugs.php.net/fix.php?id=71239&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=71239&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=71239&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=71239&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=71239&r=mysqlcfg