Adding DataFrames in pandas

Question

I have DataFrames which have different name's but are all indexed by the same time series. Now I would like to add the values in them. So far I'm using a for loop for this.
If I use df1 + df2 I get a DataFrame with the same index but with a column for each name with all NaN values in them.
If I use df1.add(df2) (with an optional fill_value=0) I get a DataFrame with the values of the first DataFrame, which is the same result as when I use df1.combineAdd(df2).

Any hints on how to add the values except for looping over all the indexes and adding the values?

Answer 1

If you know the index is the same between the two and you don't care about the column names, just do:

DataFrame(df1.values + df2.values, df1.index, df1.columns)