span>(<span class='fl'>1</span>,<span class='fl'>0</span>,<span class='fl'>0</span>,<span class='fl'>1</span>,<span class='fl'>0</span>), <span class='kw'>pre_item2</span> <span class='kw'>=</span> <span class='fu'>c</span>(<span class='fl'>1</span>,<span class='fl'>NA</span>,<span class='fl'>0</span>,<span class='fl'>1</span>,<span class='fl'>0</span>))
<span class='no'>pst_test</span> <span class='kw'>&lt;-</span> <span class='fu'>data.frame</span>(<span class='kw'>pst_item1</span> <span class='kw'>=</spa