Merging two dataframes in pandas without column names (new to pandas)

Short explanation:

If you have duplicate column names in your data, be sure to rename one column when you read the file.

If you have NaN etc in your data, remove those.

Then merge using correct answer below.

---

Probably a pretty simple question.

I have two datasets that I read in using pandas.read_csv().

My data is in two separate csv.

With the following code:

        import mibian
        import pandas as pd


        underlying = pd.read_csv("txt1.csv", names=['dt1','price']);

        options = pd.read_csv("txt2.txt", names=['dt2','ticker','maturity','strike','cP','px','strike','yield','rF','T','rlzd10']);

        merged = underlying.merge(options, left_on='dt1', right_on='dt2');

My two data heads look like this:

>>> underlying.head();

          0         1
0  20040326  3.579987
1  20040329  3.690494
2  20040330  3.755247
3  20040331  3.719373
4  20040401  3.728671

and

>>> options.head();

         0     1         2     3     4      5     6   7      8         9                10

0  20130628  SVXY  20130817  32.5  call  39.22  32.5   0  0.005  0.136986   0.411224

So my column 0 on either data set is the key i want to merge on, and i want to keep all data from both result sets.

How would I go about doing this? All the examples I am finding online require keys, but I do not have that in my results.

But on the join I get the following errors:

                            Traceback (most recent call last):
                              File "<stdin>", line 1, in <module>
                              File "/Applications/Spyder.app/Contents/Resources/lib/python2.7/spyderlib/widgets/externalshell/sitecustomize.py", line 540, in runfile
                                execfile(filename, namespace)
                              File "/Users/jasonmellone/.spyder2/.temp.py", line 12, in <module>
                                merged = underlying.merge(options, left_on='dt1', right_on='dt2',how='outer');
                              File "/Library/Python/2.7/site-packages/pandas-0.13.0-py2.7-macosx-10.9-intel.egg/pandas/core/frame.py", line 3723, in merge
                                suffixes=suffixes, copy=copy)
                              File "/Library/Python/2.7/site-packages/pandas-0.13.0-py2.7-macosx-10.9-intel.egg/pandas/tools/merge.py", line 40, in merge
                                return op.get_result()
                              File "/Library/Python/2.7/site-packages/pandas-0.13.0-py2.7-macosx-10.9-intel.egg/pandas/tools/merge.py", line 197, in get_result
                                result_data = join_op.get_result()
                              File "/Library/Python/2.7/site-packages/pandas-0.13.0-py2.7-macosx-10.9-intel.egg/pandas/tools/merge.py", line 722, in get_result
                                return BlockManager(result_blocks, self.result_axes)
                              File "/Library/Python/2.7/site-packages/pandas-0.13.0-py2.7-macosx-10.9-intel.egg/pandas/core/internals.py", line 1954, in __init__
                                self._set_ref_locs(do_refs=True)
                              File "/Library/Python/2.7/site-packages/pandas-0.13.0-py2.7-macosx-10.9-intel.egg/pandas/core/internals.py", line 2091, in _set_ref_locs
                                'have _ref_locs set' % (block, labels))
                            AssertionError: Cannot create BlockManager._ref_locs because block [IntBlock: [dt1], 1 x 372145, dtype: int64] with duplicate items [Index([u'dt1', u'price', u'dt2', u'ticker', u'maturity', u'strike', u'cP', u'px', u'strike', u'yield', u'rF', u'T', u'rlzd10'], dtype='object')] does not have _ref_locs set

I searched through my data sets and there are no duplicates.

Thank you!