Add itertools' .join()

Author: root

src/itercheat/itercheat.html

@@ -729,6 +729,21 @@ <h2>Values</h2>
             <td>\(\text{None}\)</td>
         </tr>
 
+        <tr>
+            <td>IT</td>
+            <td>join</td>
+            <td>\(\{a_0, a_1, \ldots\, a_{n-1}\}\),</td>
+            <td>\(sep: \text{&amp;str}\)</td>
+            <td>\(
+                \begin{array}{ll}
+                d(a_0) \circ sep \circ d(a_1) \circ \ldots \circ sep \circ d(a_{n-1}) \text { wh.}\\~~
+                d \text{ is Display::fmt, } \circ \text{ is string concatenation} \\
+                \end{array}
+                \)
+            </td>
+        </tr>
+
+
         <tr>
             <td rowspan="3">Std</td>
             <td rowspan="3">max</td>
@@ -1145,4 +1160,4 @@ <h2>Notes</h2>
 
     </script>
 </body>
-</html>
+</html>