php程序中if(1==$user)和if($user==1)在效率上有区别吗？

$ time php test.php

real 0m12.352s
user 0m0.000s
sys 0m0.015s

$ time php test1.php

real 0m12.240s
user 0m0.000s
sys 0m0.031s

$ time php test2.php

real 0m4.635s
user 0m0.015s
sys 0m0.000s

$ time php test3.php

real 0m4.620s
user 0m0.000s
sys 0m0.015s