> I want to learn a programming language that is easy, cross platform and
able to run it as a script without compiling.
Python is a good choice, then. The only system commonly in use that Python
doesn't come on by default is Windows.
> I have compiled programs in the pass some took a long time while others
were fast. What causes them to be slow or fast?
Talking about how long it takes to compile, or how fast they run?
The former question isn't important for interpreted languages. Python source
code gets compiled into bytecode too fast for it to be noticeable. You might
even be under the false impression that the source code is executed directly.
the latter question is extremely complicated. The answer varies a lot. Some
things generally make programs faster: compiling to machine code (like C)
generally produces faster code than running bytecode in an interpreter (like
Python). In the case of interpreted languages, using a JIT compiler (like
PyPy) can speed things up. But other than that, the cause of execution speed
depends on the specific case.
