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Flake8 extension for enforcing trailing commas in python


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Flake8 Extension to enforce better comma placement.

Build Status PyPI - Version


If you are using flake8 it's as easy as:

pip install flake8-commas

Now you can avoid those annoying merge conflicts on dictionary and list diffs.


Different versions of python require commas in different places. Ignore the errors for languages you don't use in your flake8 config:

Code message
C812 missing trailing comma
C813 missing trailing comma in Python 3
C814 missing trailing comma in Python 2
C815 missing trailing comma in Python 3.5+
C816 missing trailing comma in Python 3.6+
C818 trailing comma on bare tuple prohibited
C819 trailing comma prohibited


lookup_table = {
    'key1': 'value',
    'key2': 'something'  # <-- missing a trailing comma

json_data = json.dumps({
    "key": "value",
}),                      # <-- incorrect trailing comma. json_data is now a tuple. Likely by accident.

Related tools

You may wish to consider one of the following tools alongside or instead of flake8-commas.

For automatic insertion of commas, though noting that these tools may implement different rules around where commas should be placed: