data1.loc[:,['MarkDown1']] = data1.loc[:,['MarkDown1']].fillna(0)
Here is what the above code is Doing:
1. We are creating a new dataframe called data1.
2. We are copying the data from the original dataframe into the new dataframe.
3. We are dropping the columns that we don’t need.
4. We are filling in the missing values with 0.