Added a description to the examples.

Author: elmq0022

pandas/core/frame.py

@@ -256,8 +256,11 @@
 4  bar        2  bar        6
 5  baz        3  baz        7
 
+Merge DataFrames A and B. Specify the left and right suffix
+to append to the name of any overlapping columns.
+
 >>> A.merge(B, left_on='lkey', right_on='rkey', how='outer',
-    suffixes=('_left', '_right'))
+...         suffixes=('_left', '_right'))
   lkey  value_left rkey  value_right
 0  foo           1  foo            5
 1  foo           1  foo            8
@@ -266,10 +269,13 @@
 4  bar           2  bar            6
 5  baz           3  baz            7
 
+Merge DataFrames A and B, but throw an error if the DataFrames have
+any overlapping columns.
+
 >>> A.merge(B, left_on='lkey', right_on='rkey', how='outer',
-    suffixes=(False, False))
+...         suffixes=(False, False))
 Traceback (most recent call last):
-    ...
+...
 ValueError: columns overlap but no suffix specified:
     Index(['value'], dtype='object')
 """