I have written the following mapping in my vimrc:
autocmd FileType python :iabbrev <buffer> for for item in:<left>
After I source the python file it works. However, now whenever I type in for in the vimrc file, I get that same iabbrev behavior, even if I re-set ft=vim in that file. Why does this abbreviation occur across/outside of files I specify? Is there a way to get rid of this?
The keyword is <buffer>, not <filetype>.
It exactly means what it says: it affects the current buffer. Once the event has been triggered, the mapping exists in the current buffer, and it'll stay forever.
If you change the filetype, you'll just trigger another event that may define new things, and maybe override a few that already exist.
If you really plan to change the filetype of the current buffer, definitively use a ftplugin, and at the end fill the b:undo_ftplugin variable with all the things you have defined and that you wish to see undone.
keyword or do you mean it more colloquially, like "The important term here is..." ?
filetype of the current buffer, definitively use a ftplugin. Would you be able to show the most basic way to create a ftplugin with the above command? i.e., where would it go and would I just copy-paste the command in or does it require other stuff?