Using <space> as prefix key in normal mode, cursor will advance one character itself

Question

I put key mapping like this nnoremap <space>d "_d in my .vimrc, so I can delete text more comfortable. But when I in visual mode or visual block mode, the cursor will advance one more column, and delete more than I wanted.
I know I can change <space> to other key, like <alt>, and it works fine. But <space> is the most easily to pressed, I still want to use it. Is there any way to solve this problem? Thank you.

Answer 1

Just add the same mapping in Visual mode as well:

nnoremap <space>d "_d
xnoremap <space>d "_d

You can also use a simple noremap, which maps in Normal, Visual and Selection mode, just in that case you might want to undo the mapping in Selection mode (which is probably inappropriate for that mode):

noremap <space>d "_d
sunmap <space>d