What is the best way to create a new empty list in Python?
l = 
l = list()
I am asking this because of two reasons:
Here is how you can test which piece of code is faster:
% python -mtimeit "l=" 10000000 loops, best of 3: 0.0711 usec per loop % python -mtimeit "l=list()" 1000000 loops, best of 3: 0.297 usec per loop
However, in practice, this initialization is most likely an extremely small part of your program, so worrying about this is probably wrong-headed.
Readability is very subjective. I prefer
, but some very knowledgable people, like Alex Martelli, prefer
list() because it is pronounceable.
list() is inherently slower than
there is symbol lookup (no way for python to know in advance if you did not just redefine list to be something else!),
there is function invocation,
then it has to check if there was iterable argument passed (so it can create list with elements from it) ps. none in our case but there is "if" check
In most cases the speed difference won't make any practical difference though.