Expandtab converts spaces to newline character?

Question

When I enabled expandtab in vim by putting these in .vimrc:

set tw=4
set expandtab

Vim comverted every space typed by me to a newline character.
Like with the above settings whenever I type a new word and hit space
I get a new line.

Example:

What I want to type:
while (x < y):

What I get:
while
(x
<
y):

Answer 1

You set the textwith (tw) to 4. So Vim breaks the lines.

I guess you want shiftwidth:

set shiftwidth=4
set tabstop=4
set expandtab