python - Constructing pandas DataFrame from values in variables gives "ValueError: If using all scalar values, you must pass an index"

Question

This may be a simple question, but I can not figure out how to do this. Lets say that I have two variables as follows.

a = 2
b = 3

I want to construct a DataFrame from this:

df2 = pd.DataFrame({'A':a,'B':b})

This generates an error:

ValueError: If using all scalar values, you must pass an index

I tried this also:

df2 = (pd.DataFrame({'a':a,'b':b})).reset_index()

This gives the same error message.

Answer 1

The error message says that if you're passing scalar values, you have to pass an index. So you can either not use scalar values for the columns -- e.g. use a list:

>>> df = pd.DataFrame({'A': [a], 'B': [b]})
>>> df
   A  B
0  2  3

or use scalar values and pass an index:

>>> df = pd.DataFrame({'A': a, 'B': b}, index=[0])
>>> df
   A  B
0  2  3