Python and the need for speed
marko at pacujo.net
Wed Apr 12 06:11:00 EDT 2017
bart4858 at gmail.com:
> On Wednesday, 12 April 2017 07:48:57 UTC+1, Steven D'Aprano wrote:
>> Here's another example:
>> answer = 0
>> for i in range(10):
>> answer += 1
>> instead of
>> answer = 10
>> So... how exactly does the compiler prohibit stupid code?
> Actually, an optimising C compiler (not one of mine!) probably could
> reduce that to answer=10.
One of the reasons C compilers need to address "stupid" code like that
is that it may arise from macros or from generated code. Maybe the
statement "answer += 1" is "answer = answer * 1.01 + 0.0001" in some
other (compile-time) circumstances.
A similar situation can hit Python as well through a (virtual) method
call, a dynamic function call or a conditional import, for example.
More information about the Python-list