Selecting every other node uing XPATH

Question

Given an arbitrary amount nodes to select:

<root>
  <foo>1</foo>
  <foo>2</foo>
  <foo>3</foo>
  <foo>4</foo>
  <!-- ... -->
<root>

How do I select every other foo so that I get foo[1], foo[3], ... ?

Answer 1

Try

/root/foo[position() mod 2 = 1]

No idea if it will work right, might need 0. I forget if position starts at 0 or 1