gt;</span> <span style="color: #BCBCBC;">1</span> a     a         1     0      0     0      0</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> <span style="color: #BCBCBC;">2</span> b     <span style="color: #BB0000;">NA</span>        2     1      0     0      1</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> <span style="color: #BCBCBC;">3</span> <span style="color: #BB0000;">NA</span>    c         3     0      1     1      0</span>
<span class="r-in"><span></span></span>
<span c