diff --git a/docs/HTML/DataFrame.html b/docs/HTML/DataFrame.html
index 1718214f..1c63bdb0 100644
--- a/docs/HTML/DataFrame.html
+++ b/docs/HTML/DataFrame.html
@@ -1217,6 +1217,18 @@ <H2><font color="blue">API Reference with code samples</font></H2>
       <td title="Time frquency types">enum class <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/time_frequency.html">time_frequency</a>{}</td>
     </tr>
 
+    <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
+      <td title="Memory usage structure">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/get_memory_usage.html">MemUsage</a>{}</td>
+    </tr>
+
+    <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
+      <td title="String column statistics structure">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/get_str_col_stats.html">StringStats</a>{}</td>
+    </tr>
+
+    <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
+      <td style="text-align:center;background-color:SlateGrey;color:white">Arithmetic<BR>Operators</td>
+    </tr>
+
     <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
       <td title="Division operator for DataFrames">operator <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/global_operators.html">df_divides</a>()</td>
     </tr>
@@ -1249,6 +1261,10 @@ <H2><font color="blue">API Reference with code samples</font></H2>
       <td title="Plus operator for DataFrames">operator <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/global_operators.html">scaler_df_plus</a>()</td>
     </tr>
 
+    <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
+      <td style="text-align:center;background-color:SlateGrey;color:white">Exceptions</td>
+    </tr>
+
     <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
       <td title="An exception type">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/DataFrameTypes.html">BadRange</a>{}</td>
     </tr>
@@ -1265,10 +1281,6 @@ <H2><font color="blue">API Reference with code samples</font></H2>
       <td title="An exception type">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/DataFrameTypes.html">InconsistentData</a>{}</td>
     </tr>
 
-    <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
-      <td title="Memory usage structure">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/get_memory_usage.html">MemUsage</a>{}</td>
-    </tr>
-
     <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
       <td title="An exception type">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/DataFrameTypes.html">NotFeasible</a>{}</td>
     </tr>
@@ -1277,9 +1289,6 @@ <H2><font color="blue">API Reference with code samples</font></H2>
       <td title="An exception type">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/DataFrameTypes.html">NotImplemented</a>{}</td>
     </tr>
 
-    <tr class="item" onmouseover="this.style.backgroundColor='#ffff66';" onmouseout="this.style.backgroundColor='#d4e3e5';">
-      <td title="String column statistics structure">struct <a href="https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/get_str_col_stats.html">StringStats</a>{}</td>
-    </tr>
   </table>
   </div>