I have two datasets where the first dataset value is changing according to the number of objects I detected. My second dataset is a constant value where these columns should be joined with the first dataset. Now the problem is that if I have 50 rows in the first dataset and 20 rows in the second dataset. How are the remaining rows of the second dataset filled as they have a constant value?

df1 = pd.read_csv('file1.csv')
df1.head()

df2 = pd.read_csv('file2.csv)
df2.head()

Now I joined these two tables:

df_join = df1.join(df2, rsuffix='_right')
df_join.head()

how to these constant value increase based on the number of rows in df1? Now they are NaN. For example, the column BitSizeValue is 8.0, this show fill all the row of the same column.

CodePudding user response：

To fill constant values? You mean you need to fill that Extra Nan with constant values that are above?

If so

df_join=df_join.fillna(method='ffill')
df_join.head()