Problem encountered while updating a particular cell of a pandas data frame in Python I am trying to read in an excel file into a pandas data frame using pandas.read_excel() function. The first column is 'Date'. The first entry into that column has asterisk mark which I want to remove. Here are the first 2 rows of the data frame DF.
0   1/4/1996*   11540   10841   3592    1827    26476   14510   6900    0   0   NaN NaN NaN NaN NaN NaN NaN NaN NaN 
1   1996-01-11 00:00:00 13881   11735   2532    4188    32064   21989   3819    2586    0   NaN NaN`

In order to remove that *, I am doing this:DF['Date'][0] = '1/4/1996'. However, once I do that, I am getting a warning message
/anaconda/lib/python2.7/site-packages/ipykernel/__main__.py:3: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame

See the the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
  app.launch_new_instance()

and it changes the cell value, but, it also attaches another 'Date' column at the end of the df like this:
0   1/4/1996   11540   10841   3592    1827    26476   14510   6900    0   0   NaN NaN NaN NaN NaN NaN NaN NaN NaN 1/4/1996

I don't understand why this is happening.
I would greatly appreciate it if someone can explain this or point out the correct way of changing the cell value.
Use a combination of string processing and type casting to process the whole column in one swoop:


  excelDF[datecol] = pandas.to_datetime(excelDF[datecol].str.replace('*',''))


I tried using str.rstrip('*') but I could not get it to work.