Why can't I merge pandas dataframes

[learnpython2018]

Thanks. Here is the updated code to display head:

ratings = pd.read_csv('title.ratings.tsv', sep = '\t').drop_duplicates(subset = 'tconst', keep = 'first')
titles = pd.read_csv('title.akas.tsv', sep = '\t').drop_duplicates(subset = 'titleId', keep = 'first')
print titles.head()
print ratings.head()
titles.merge(titles, ratings, left_on="titleId", right_on="tconst")

The error:

Error:
  File "mihika1.py", line 8, in <module>
    titles.merge(titles, ratings, left_on="titleId", right_on="tconst")
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/frame.py", line 5370, in merge
    copy=copy, indicator=indicator, validate=validate)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/reshape/merge.py", line 57, in merge
    validate=validate)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/reshape/merge.py", line 565, in __init__
    self.join_names) = self._get_merge_keys()
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/reshape/merge.py", line 824, in _get_merge_keys
    right_keys.append(right[rk]._values)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/frame.py", line 2139, in __getitem__
    return self._getitem_column(key)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/frame.py", line 2146, in _getitem_column
    return self._get_item_cache(key)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/generic.py", line 1842, in _get_item_cache
    values = self._data.get(item)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/internals.py", line 3843, in get
    loc = self.items.get_loc(item)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/indexes/base.py", line 2527, in get_loc
    return self._engine.get_loc(self._maybe_cast_indexer(key))
  File "pandas/_libs/index.pyx", line 117, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/index.pyx", line 139, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi", line 1265, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi", line 1273, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'tconst'

The output from the head

Output:
sys:1: DtypeWarning: Columns (7) have mixed types. Specify dtype option on import or set low_memory=False.
      titleId  ordering                      title region language  \
0   tt0000001         1  Carmencita - spanyol tánc     HU       \N   
4   tt0000002         1     Le clown et ses chiens     \N       \N   
10  tt0000003         1           Sarmanul Pierrot     RO       \N   
16  tt0000004         1                Un bon bock     \N       \N   
22  tt0000005         1        Blacksmithing Scene     US       \N   

          types attributes isOriginalTitle  
0   imdbDisplay         \N               0  
4      original         \N               1  
10  imdbDisplay         \N               0  
16     original         \N               1  
22  alternative         \N               0  
      tconst  averageRating  numVotes
0  tt0000001            5.8      1412
1  tt0000002            6.4       167
2  tt0000003            6.6      1006
3  tt0000004            6.4       100
4  tt0000005            6.2      1708

---

What a stupid mistake

titles.merge(titles, ratings, left_on="titleId", right_on="tconst")

should have been:

pd.merge(titles, ratings, left_on="titleId", right_on="tconst")