"Finally, slowness, until you get really low-down is relatively easy problem with many solutions."
There is a barrier that you can hit in Python/Perl/Ruby/Javascript where you're trying to do something, you've optimized the Python/etc. to within an inch of its life, and it's still just too slow. I've hit it twice now in pretty serious ways. Once you've removed all the slowness-that-has-easy-solutions, you're still using a very slow language... the 50-100x number I cite is with the slowness already removed for optimal code, though, to be fair, this is in comparison to fairly optimal C/C++ as well. Well-written Python can be competitive with poorly-written C, and that is also not even slightly a joke, since it's generally easier to get to the well-written Python. But you can still run out of juice on a modern machine.
But ultimately this is just something you want to know and understand, and not be too bedazzled by claims that everything's hunky dory in every way.
"Finally, slowness, until you get really low-down is relatively easy problem with many solutions."
There is a barrier that you can hit in Python/Perl/Ruby/Javascript where you're trying to do something, you've optimized the Python/etc. to within an inch of its life, and it's still just too slow. I've hit it twice now in pretty serious ways. Once you've removed all the slowness-that-has-easy-solutions, you're still using a very slow language... the 50-100x number I cite is with the slowness already removed for optimal code, though, to be fair, this is in comparison to fairly optimal C/C++ as well. Well-written Python can be competitive with poorly-written C, and that is also not even slightly a joke, since it's generally easier to get to the well-written Python. But you can still run out of juice on a modern machine.
But ultimately this is just something you want to know and understand, and not be too bedazzled by claims that everything's hunky dory in every way.