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Differences between Autoflake and Unimport

  • Autoflake doesn’t always remove the duplicate imports when they are on separate lines.


from os import walk
from os import walk


For this snippet, autoflake doesn’t change anything, while unimport detects and removes the first walk import.

  • Autoflake replaces unused imports in compound statements with pass, while unimport detects and imports inside compound statements, if it detects that you are expecting an ImportError, it doesn’t remove that particular import.
    from x import y
except ImportError:

For this snippet autoflake replaces the import statement with pass., while unimport leaves it as is.

  • Autoflake is not accurate when it comes to star import expansions, while unimport can detect and expand them accurately.
from math import *


Running autoflake with –expand-star-import flag on the snippet above turns it into

from math import RANDOM_VAR

while unimport simple removes the math import because it is not used.

  • Autoflake doesn’t work with multiple star imports, while unimport does.

from math import _ from os import _

use(walk, cos)

Running unimport on the above snippet with –include-star-imports flag produces the correct output.

from math import cos
from os import walk

use(walk, cos)

while autoflake simply ignores them.

  • Our outputs are more useful, try using our –check, –diff or –permission commands.

Unimport < 0.6.8 was much slower than Autoflake == 1.4 (current latest version as of writing this) but Unimport > 0.6.8 is slightly faster.

Reasons to choose autoflake
  • It is faster. When tested, autoflake is 1-4x faster on average. (Unimport is slightly faster now)
  • It removes unused variables which unimport doesn’t support, and is not planning to.
  • Has a feature that removes duplicate keys on objects.
Reasons to choose unimport
  • It does more static analysis to increase the accuracy of choosing the correct imports to remove.
  • Can handle star imports more accurately.( describes their approach)
  • Works with multiple star imports.
  • Removes duplicate imports.
  • Has skip_file feature that allows one to skip an entire file.
  • Allows configuration via pyproject.toml and setup.cfg files.

Even though unimport and autoflake has features that are similar, they are not designed to do the same thing. When you are including one to your project, it is a good idea to know what your needs are, and decide accordingly.

I can already do this with many IDEs, why should I use Unimport?

Short answer

Not everyone works with IDEs and not all IDEs work in all environments.

Long answer

Imagine that you are working with a team where everyone may not have the same coding environment. For instance, not everyone uses PyCharm or VSCode. In such a scenario, if you want to apply certain standards, you can use pre-commit. It can be helpful. Furthermore, if you want to ensure that unnecessary imports are removed before committing, you should use Unimport with pre-commit. Let’s assume that you want to ensure that there are no unnecessary imports in your entire project. In that case, Unimport will help you achieve this goal.

Last update: July 7, 2023
Created: July 7, 2023