pfhayes / isort

A Python utility / library to sort imports.

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isort your python imports for you so you don't have to.

isort is a Python utility / library to sort imports alphabetically, and automatically separated into sections. It provides a command line utility, Python library and plugins for various editors to quickly sort all your imports. It requires Python 3.4+ to run but supports formatting Python 2 code too.

Before isort:

from my_lib import Object

print("Hey")

import os

from my_lib import Object3

from my_lib import Object2

import sys

from third_party import lib15, lib1, lib2, lib3, lib4, lib5, lib6, lib7, lib8, lib9, lib10, lib11, lib12, lib13, lib14

import sys

from __future__ import absolute_import

from third_party import lib3

print("yo")

After isort:

from __future__ import absolute_import

import os
import sys

from third_party import (lib1, lib2, lib3, lib4, lib5, lib6, lib7, lib8,
                         lib9, lib10, lib11, lib12, lib13, lib14, lib15)

from my_lib import Object, Object2, Object3

print("Hey")
print("yo")

Installing isort

Installing isort is as simple as:

pip install isort

Install isort with requirements.txt support:

pip install isort[requirements]

Install isort with Pipfile support:

pip install isort[pipfile]

Install isort with both formats support:

pip install isort[requirements,pipfile]

Using isort

From the command line:

isort mypythonfile.py mypythonfile2.py

or recursively:

isort -rc .

which is equivalent to:

isort **/*.py

or to see the proposed changes without applying them:

isort mypythonfile.py --diff

Finally, to atomically run isort against a project, only applying changes if they don't introduce syntax errors do:

isort -rc --atomic .

(Note: this is disabled by default as it keeps isort from being able to run against code written using a different version of Python)

From within Python:

from isort import SortImports

SortImports("pythonfile.py")

or:

from isort import SortImports

new_contents = SortImports(file_contents=old_contents).output

From within Kate:

ctrl+[

or:

menu > Python > Sort Imports

Installing isort's Kate plugin

For KDE 4.13+ / Pate 2.0+:

wget https://raw.github.com/timothycrosley/isort/master/kate_plugin/isort_plugin.py --output-document ~/.kde/share/apps/kate/pate/isort_plugin.py
wget https://raw.github.com/timothycrosley/isort/master/kate_plugin/isort_plugin_ui.rc --output-document ~/.kde/share/apps/kate/pate/isort_plugin_ui.rc
wget https://raw.github.com/timothycrosley/isort/master/kate_plugin/katepart_isort.desktop --output-document ~/.kde/share/kde4/services/katepart_isort.desktop

For all older versions:

wget https://raw.github.com/timothycrosley/isort/master/kate_plugin/isort_plugin_old.py --output-document ~/.kde/share/apps/kate/pate/isort_plugin.py

You will then need to restart kate and enable Python Plugins as well as the isort plugin itself.

Installing isort's for your preferred text editor

Several plugins have been written that enable to use isort from within a variety of text-editors. You can find a full list of them on the isort wiki. Additionally, I will enthusiastically accept pull requests that include plugins for other text editors and add documentation for them as I am notified.

How does isort work?

isort parses specified files for global level import lines (imports outside of try / except blocks, functions, etc..) and puts them all at the top of the file grouped together by the type of import:

• Future
• Python Standard Library
• Third Party
• Current Python Project
• Explicitly Local (. before import, as in: from . import x)
• Custom Separate Sections (Defined by forced_separate list in configuration file)
• Custom Sections (Defined by sections list in configuration file)

Inside of each section the imports are sorted alphabetically. isort automatically removes duplicate python imports, and wraps long from imports to the specified line length (defaults to 79).

When will isort not work?

If you ever have the situation where you need to have a try / except block in the middle of top-level imports or if your import order is directly linked to precedence.

For example: a common practice in Django settings files is importing * from various settings files to form a new settings file. In this case if any of the imports change order you are changing the settings definition itself.

However, you can configure isort to skip over just these files - or even to force certain imports to the top.

Configuring isort

If you find the default isort settings do not work well for your project, isort provides several ways to adjust the behavior.

To configure isort for a single user create a ~/.isort.cfg or $XDG_CONFIG_HOME/isort.cfg file:

[settings]
line_length=120
force_to_top=file1.py,file2.py
skip=file3.py,file4.py
known_future_library=future,pies
known_standard_library=std,std2
known_third_party=randomthirdparty
known_first_party=mylib1,mylib2
indent='    '
multi_line_output=3
length_sort=1
forced_separate=django.contrib,django.utils
default_section=FIRSTPARTY
no_lines_before=LOCALFOLDER

Additionally, you can specify project level configuration simply by placing a .isort.cfg file at the root of your project. isort will look up to 25 directories up, from the file it is ran against, to find a project specific configuration.

Or, if you prefer, you can add an isort or tool:isort section to your project's setup.cfg or tox.ini file with any desired settings.

You can also add your desired settings under a [tool.isort] section in your pyproject.toml file.

You can then override any of these settings by using command line arguments, or by passing in override values to the SortImports class.

Finally, as of version 3.0 isort supports editorconfig files using the standard syntax defined here: https://editorconfig.org/

Meaning you place any standard isort configuration parameters within a .editorconfig file under the *.py section and they will be honored.

For a full list of isort settings and their meanings take a look at the isort wiki.

Multi line output modes

You will notice above the "multi_line_output" setting. This setting defines how from imports wrap when they extend past the line_length limit and has 6 possible settings:

0 - Grid

from third_party import (lib1, lib2, lib3,
                         lib4, lib5, ...)

1 - Vertical

from third_party import (lib1,
                         lib2,
                         lib3
                         lib4,
                         lib5,
                         ...)

2 - Hanging Indent

from third_party import \
    lib1, lib2, lib3, \
    lib4, lib5, lib6

3 - Vertical Hanging Indent

from third_party import (
    lib1,
    lib2,
    lib3,
    lib4,
)

4 - Hanging Grid

from third_party import (
    lib1, lib2, lib3, lib4,
    lib5, ...)

5 - Hanging Grid Grouped

from third_party import (
    lib1, lib2, lib3, lib4,
    lib5, ...
)

6 - Hanging Grid Grouped, No Trailing Comma

In Mode 5 isort leaves a single extra space to maintain consistency of output when a comma is added at the end. Mode 6 is the same - except that no extra space is maintained leading to the possibility of lines one character longer. You can enforce a trailing comma by using this in conjunction with -tc or trailing_comma: True.

from third_party import (
    lib1, lib2, lib3, lib4,
    lib5
)

7 - NOQA

from third_party import lib1, lib2, lib3, ...  # NOQA

Alternatively, you can set force_single_line to True (-sl on the command line) and every import will appear on its own line:

from third_party import lib1
from third_party import lib2
from third_party import lib3
...

Note: to change the how constant indents appear - simply change the indent property with the following accepted formats: * Number of spaces you would like. For example: 4 would cause standard 4 space indentation. * Tab * A verbatim string with quotes around it.

For example:

"    "

is equivalent to 4.

For the import styles that use parentheses, you can control whether or not to include a trailing comma after the last import with the include_trailing_comma option (defaults to False).

Intelligently Balanced Multi-line Imports

As of isort 3.1.0 support for balanced multi-line imports has been added. With this enabled isort will dynamically change the import length to the one that produces the most balanced grid, while staying below the maximum import length defined.

Example:

from __future__ import (absolute_import, division,
                        print_function, unicode_literals)

Will be produced instead of:

from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

To enable this set balanced_wrapping to True in your config or pass the -e option into the command line utility.

Custom Sections and Ordering

You can change the section order with sections option from the default of:

FUTURE,STDLIB,THIRDPARTY,FIRSTPARTY,LOCALFOLDER

to your preference:

sections=FUTURE,STDLIB,FIRSTPARTY,THIRDPARTY,LOCALFOLDER

You also can define your own sections and their order.

Example:

known_django=django
known_pandas=pandas,numpy
sections=FUTURE,STDLIB,DJANGO,THIRDPARTY,PANDAS,FIRSTPARTY,LOCALFOLDER

would create two new sections with the specified known modules.

The no_lines_before option will prevent the listed sections from being split from the previous section by an empty line.

Example:

sections=FUTURE,STDLIB,THIRDPARTY,FIRSTPARTY,LOCALFOLDER
no_lines_before=LOCALFOLDER

would produce a section with both FIRSTPARTY and LOCALFOLDER modules combined.

Auto-comment import sections

Some projects prefer to have import sections uniquely titled to aid in identifying the sections quickly when visually scanning. isort can automate this as well. To do this simply set the import_heading_{section_name} setting for each section you wish to have auto commented - to the desired comment.

For Example:

import_heading_stdlib=Standard Library
import_heading_firstparty=My Stuff

Would lead to output looking like the following:

# Standard Library
import os
import sys

import django.settings

# My Stuff
import myproject.test

Ordering by import length

isort also makes it easy to sort your imports by length, simply by setting the length_sort option to True. This will result in the following output style:

from evn.util import (
    Pool,
    Dict,
    Options,
    Constant,
    DecayDict,
    UnexpectedCodePath,
)

It is also possible to opt-in to sorting imports by length for only specific sections by using length_sort_ followed by the section name as a configuration item, e.g.:

length_sort_stdlib=1

Skip processing of imports (outside of configuration)

To make isort ignore a single import simply add a comment at the end of the import line containing the text isort:skip:

import module  # isort:skip

or:

from xyz import (abc,  # isort:skip
                 yo,
                 hey)

To make isort skip an entire file simply add isort:skip_file to the module's doc string:

""" my_module.py
    Best module ever

   isort:skip_file
"""

import b
import a

Adding an import to multiple files

isort makes it easy to add an import statement across multiple files, while being assured it's correctly placed.

From the command line:

isort -a "from __future__ import print_function" *.py

from within Kate:

ctrl+]

or:

menu > Python > Add Import

Removing an import from multiple files

isort also makes it easy to remove an import from multiple files, without having to be concerned with how it was originally formatted.

From the command line:

isort -rm "os.system" *.py

from within Kate:

ctrl+shift+]

or:

menu > Python > Remove Import

Using isort to verify code

The --check-only option

isort can also be used to used to verify that code is correctly formatted by running it with -c. Any files that contain incorrectly sorted and/or formatted imports will be outputted to stderr.

isort **/*.py -c -vb

SUCCESS: /home/timothy/Projects/Open_Source/isort/isort_kate_plugin.py Everything Looks Good!
ERROR: /home/timothy/Projects/Open_Source/isort/isort/isort.py Imports are incorrectly sorted.

One great place this can be used is with a pre-commit git hook, such as this one by @acdha:

https://gist.github.com/acdha/8717683

This can help to ensure a certain level of code quality throughout a project.

Git hook

isort provides a hook function that can be integrated into your Git pre-commit script to check Python code before committing.

To cause the commit to fail if there are isort errors (strict mode), include the following in .git/hooks/pre-commit:

#!/usr/bin/env python
import sys
from isort.hooks import git_hook

sys.exit(git_hook(strict=True, modify=True))

If you just want to display warnings, but allow the commit to happen anyway, call git_hook without the strict parameter. If you want to display warnings, but not also fix the code, call git_hook without the modify parameter.

Setuptools integration

Upon installation, isort enables a setuptools command that checks Python files declared by your project.

Running python setup.py isort on the command line will check the files listed in your py_modules and packages. If any warning is found, the command will exit with an error code:

$ python setup.py isort

Also, to allow users to be able to use the command without having to install isort themselves, add isort to the setup_requires of your setup() like so:

setup(
    name="project",
    packages=["project"],

    setup_requires=[
        "isort"
    ]
)

Why isort?

isort simply stands for import sort. It was originally called "sortImports" however I got tired of typing the extra characters and came to the realization camelCase is not pythonic.

I wrote isort because in an organization I used to work in the manager came in one day and decided all code must have alphabetically sorted imports. The code base was huge - and he meant for us to do it by hand. However, being a programmer - I'm too lazy to spend 8 hours mindlessly performing a function, but not too lazy to spend 16 hours automating it. I was given permission to open source sortImports and here we are :)

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Thanks and I hope you find isort useful!

~Timothy Crosley