Vim delete all lines that has only one letter

Question

In Vim is it possible to delete lines that has only one letter?

For example

This
is
an
x
z
example
c

would turn into

This
is
an
example

Answer 1

:g/^.$/d

: — switch to the command line;

g — run a global command over all lines;

/^.$/ — find a line that has exactly one character; beginning of the line, any character, end of the line;

d — delete the line.