fixed not defined pop array in pandas.rst

Author: alixdamman

doc/source/tutorial/pandas.rst

@@ -4,6 +4,9 @@ Compatibility with pandas
 To convert an Array object into a pandas DataFrame, the method :py:meth:`~Array.to_frame` can be used:
 
 .. ipython:: python
+    from larray import *
+    csv_dir = get_example_filepath('examples')
+    pop = read_csv(csv_dir + '/pop.csv')
 
     df = pop.to_frame()
     df