pand table or matrix to data frame</td>
</tr>
<tr class="even">
<td align="left">fac2num</td>
<td align="left">Convert factor to numeric vector</td>
</tr>
<tr class="odd">
<td align="left">filldown</td>
<td align="left">Fill down NA with the last observed observation</td>
</tr>
<tr class="even">
<td align="left">ht</td>
<td align="left">Show the head and tail of an object</td>
</tr>
<tr class="odd">
<td align="left">lower.tri.vector</td>
<td align="left">Split Matrix by Clusters and Return Lower Triangular 