Python version 3.4 vs 3.6 pandas set_index function differences

Question

I have a pandas dataframe named Value.

Value: 
   Tenor  CurrPrice
0     on    0.123
1     1b    0.234
2     tn    0.456
3     1w    0.678

Now, when I do set_index function call in pandas version 3.4 I get:

Value.set_index('Tenor',inplace=True)
Value
     
       CurrPrice
Tenor
on      0.123
1b      0.234
tn      0.456
1w      0.678

But when I do set_index function call in pandas version 3.6 I get:

Value.set_index('Tenor',inplace=True)
Value
     
         CurrPrice
Tenor
(on,)      0.123
(1b,)      0.234
(tn,)      0.456
(1w,)      0.678

So Basically the Python 3.6 version set_index call when setting the index adding the small brackets and comma to the value, which is causing issues for my process. Two questions:

1. Why it is like this ?
2. How can I fix the Python 3.6 version output so that it becomes like python 3.4 to fix the process.

Answer 1

Having 'small brackets and a comma to the value' means, that the values are of type tuple, and not string, as in your first example.

This should result from the data of the DataFrame, and not the pd.set_index method.

Check the types of the values of the column, this should provide some clarify.

types = value['Tenor'].apply(lambda x: type(x))