ATTENTION: you probably don't need this plugin! See Why you may not need this plugin.
vim-yapf is a Vim plugin that applies yapf to your current file.
yapf automatically formats Python code, based on improved syntax styles.
yapf can be installed either with pip:
pip install yapf
or by installing with conda (OSX and linux64 only) with my binstar channel:
conda install -c https://conda.binstar.org/srwalker101 yapf
Either use a plugin manager and add Plug[in] 'mindriot101/vim-yapf' to your vimrc, or use pathogen.
The plugin does not create any bindings by default, this is left up to the user. An example could be:
:nnoremap <leader>y :call Yapf()<cr>
or
:nnoremap <leader>y :Yapf<cr>
call function
:Yapf
with arguments
:Yapf --style google
or
:call Yapf(" --style pep8")
The yapf style can be globally set, in your vimrc:
let g:yapf_style_conf = "path/to/style"
The plugin itself is very simple. It handles user options granted, but at its core it uses ex commands to perform its magic. yapf behaves like a good unix command: it takes text on stdin and spits the altered result to stdout, which is exactly what vim expects.
At its core, this plugin runs the ex command:
0,$!yapf
This pipes the range 0,$ i.e. the whole file through a shell command yapf and replaces the range with the altered result.
Instead of installing this plugin, one could add a mapping e.g.:
autocmd FileType python nnoremap <leader>y :0,$!yapf<Cr><C-o>
Alternatively yapf could be set as the formatprg for the python filetype, and reformatting can be performed with the gq{motion} operator (e.g. with visual selection) to reformat a part of the file.
Alternatively alternatively yapf could be set as the equalprg:
setlocal equalprg=yapf
and reformat the whole file with gg=G or a single line with =.