making assignment visible on web

Author: PenguinPen

doc/source/getting_started/intro_tutorials/03_subset_data.rst

@@ -335,7 +335,7 @@ the name ``anonymous`` to the first 3 elements of the fourth column:
 .. ipython:: python
 
     titanic.iloc[0:3, 3] = "anonymous"
-    titanic.head()
+    titanic..iloc[:, 3].head()
 
 .. raw:: html