yanking lines from a buffer that isn't the active one

Question

Let's say there are two loaded buffers/files and they are both displayed via split windows, line numbers are enabled and thus known.

Is there a way to stay in one buffer, specify a line of the other buffer and yank it so it can be put into the active buffer?

Answer 1

:let @0 = join(getbufline('#', 42), "\n") . "\n"

(Replace # with the name of the other buffer and 42 with the line number within the other buffer.)