How to delete every other line in Vim?

Question

I would like to delete every other line from a Vim buffer, starting with the second one, i.e., lines 2, 4, 6, etc. For example, if the buffer’s contents is:

a         


        

Answer 1

from vim mail archive:

:let i=1 | while i <= line('$') | if (i % 2) | exe i . "delete" | endif | let i += 1 | endwhile

(To be typed on one line on the vim command line, will delete row 1,3,5,7,...)