Why is casting and comparing in PHP faster than is_*?
- by tstenner
While optimizing a function in PHP, I changed
if(is_array($obj)) foreach($obj as $key=$value { [snip] }
else if(is_object($obj)) foreach($obj as $key=$value { [snip] }
to
if($obj == (array) $obj) foreach($obj as $key=$value { [snip] }
else if($obj == (obj) $obj) foreach($obj as $key=$value { [snip] }
After learning about ===, I changed that to
if($obj === (array) $obj) foreach($obj as $key=$value { [snip] }
else if($obj === (obj) $obj) foreach($obj as $key=$value { [snip] }
Changing each test from is_* to casting resulted in a major speedup (30%).
I understand that === is faster than == as no coercion has to be done, but why is casting the variable so much faster than calling any of the is_*-functions?
