alt Hacker News>The usual suspects are the GIL, interpretation, and dynamic typing. All three matter, but none of them is the real story. The real story is that Python is designed to be maximally dynamic -- you can monkey-patch methods at runtime, replace builtins, change a class's inheritance chain while instances exist -- and that design makes it fundamentally hard to optimize.
ok I guess the harder question is. Why isn't python as fast as javascript?
> ok I guess the harder question is. Why isn't python as fast as javascript?
Actually there is a pretty easy answer: worldwide, the amount of javascript being evaluated every day is many orders of magnitude higher than the amount of python. The amount of money available for optimizing it has thus been many orders of magnitude higher as well.