List Literal¶
Sourcery refactoring id: list-literal
¶
Description:¶
Replaces lists created with list()
with []
Before:¶
x = list()
After:¶
x = []
Explanation:¶
The most concise and Pythonic way to create a list is to use the []
notation.
This fits in with the way we create lists with elements, saving a bit of mental energy that might be taken up with thinking about two different ways of creating lists.
x = ["first", "second"]
Doing things this way has the added advantage of being a nice little performance improvement.
Here are the timings before and after the change:
$ python3 -m timeit "x = list()"
5000000 loops, best of 5: 63.3 nsec per loop
$ python3 -m timeit "x = []"
20000000 loops, best of 5: 15.8 nsec per loop
Similar reasoning and performance results hold for replacing dict()
with {}
.