black formatter: How can I place one newline before and after function instead of two

Question

I am using black formatter. I have two newlines before and two newlines after function definition. I want one newline before and one newline after function definition.

Can i do it using black config file black --config FILE. If so,how.

Answer 1

OP here, I ended up using yapf.

The command looks like:

yapf --style={blank_lines_around_top_level_definition=1} file_name.py

for multiple arguments:

yapf --style={based_on_style=pep8} --style={blank_lines_around_top_level_definition=1} file_name.py

In vscode you can use the yapf styles like:

"python.formatting.yapfArgs": [
    "--style",
    "{based_on_style: pep8, blank_lines_around_top_level_definition: 1}"
],

Answer 2

Using black formatter this is NOT possible. From it's documentation:

By using it, you agree to cede control over minutiae of hand-formatting._

Current style:

It uses 2 lines to visually distinguish methods from empty lines in code structure. From the docs: Black will allow single empty lines inside functions, [...] It will also insert proper spacing before and after function definitions. It’s one line before and after inner functions and two lines before and after module-level functions and classes.

From: the docs of black.readthedocs.io

Customization:

Command line options Black has quite a few knobs these days, although Black is opinionated so style configuration options are deliberately limited and rarely added. You can list them by running black --help.

You need to change the formatter you use to something different to get your effect.