I cannot figure out how to mark a region in PyCharm's emacs mode.
Normally in Emacs, one would press CTRL+Space to set the mark point at the cursor's current location, move the cursor to select the region you want to yank (cut) or copy, and then press CTRL+W to yank or ESC+W to copy the region. This is all described in at length in the manual: http://www.gnu.org/software/libtool/manual/emacs/Setting-Mark.html
However, in PyCharm's emacs mode pressing CTRL+Space is apparently mapped by default to some kind of autocomplete command (I'm new to PyCharm, sorry I can't be more specific). I cannot find anything under Preference > Keymap corresponding to setting the mark mode. The alternative Emacs mapping CTRL+@ (CTRL+SHIFT+2) does work but this is fairly awkward.
For now, I have to select regions using SHIFT+Arrow Keys. My fingers are much more used to the standard Emacs CTRL+Space so I'm hoping it is possible to customize this key mapping!