delete lines not (containing pattern and 2 lines above pattern) - vim

Question

In Vim I try to delete all lines in a file not (containing a pattern and 2 lines above the pattern). I try:
:g!/pattern/.-2 d
But it says: invalid range...
What to do?

Answer 1

The command below looks for lines that don't match pattern and deletes them and the two lines above:
:g!/pattern/-2,.d
The command below looks for lines that don't match pattern and deletes the line located two lines above:
:g!/pattern/-2d
Ranges always go downwards so we use the upper address first — -2 — and the lower one second — . —.
That said, you'll most likely get an error if a matching line doesn't have two lines above it.

Answer 2

then how should i delete all the lines exept the lines 4, 5 and 6 in the folowing file: line 1 line 2 line 3 line 4 line 5 line containing pattern line 7 ?
Like this:
:v/\v(.*\n){,2}.*pattern.*/d
This matches if:
the line contains the pattern, or
next line contains the pattern, or
the 2nd next line contains the pattern.
These lines are kept. All other lines (:v) are deleted.
Example:
"Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut
aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit
in voluptate velit esse cillum dolore eu
fugiat nulla pariatur. Excepteur sint
occaecat cupidatat non proident, sunt in
culpa qui officia deserunt mollit anim
id est laborum."
Run:
:v/\v(.*\n){,2}.*labor.*/d
Result:
consectetur adipiscing elit, -2
sed do eiusmod tempor incididunt -1
ut labore et dolore magna aliqua. <-0 labor(e)
Ut enim ad minim veniam, quis nostrud -1
exercitation ullamco laboris nisi ut <-0 labor(is)
occaecat cupidatat non proident, sunt in -2
culpa qui officia deserunt mollit anim -1
id est laborum." <-0 labor(um)