I have a pandas dataframe like this:

Q1 | Q2 | Q3 | Q4
   | 2  |    | 
1  |    |    |
   |    | 3  | 
   | 2  |    |
   |    |    | 4  

My desired output is:

Q
_
2
1
3
2
4
 

How can I do it easily in Pandas?

CodePudding user response：

You could use stack

df.stack().reset_index(drop=True).to_frame().rename({0:'Q'},axis=1)

    Q
0  2.0
1  1.0
2  3.0
3  2.0
4  4.0

CodePudding user response：

here is another way to do it

df.fillna(method='bfill', axis=1)['Q1'].astype(int).to_frame().rename(columns={'Q1':'Q'})

    Q
0   2
1   1
2   3
3   2
4   4