python - How to replace string with values from one datafame to another dataframe

Question

I have two dataframes, where in one dataframe(df1) each user is having string values, while in another dataframe (df2) there is a value associated with string values. I want to have a new dataframe similar to df1 but with string being replaced with values corresponding to df2. Let me know if a simple method exist to create such new dataframe? here are the sample query for df1 and df2

df1 = pd.DataFrame({"user": ["user1", "user2", "user3", "user4"], "p1": ["A", "C", "D", "D"],"p2": ["B", "D", "D", "A"],"p3": ["A", "B", "C", "D"],"p4": ["D", "A", "B", "C"], }, index=[0, 1, 2, 3], )

df2 = pd.DataFrame({"N1": ["A", "B", "C", "D"],"N2": ["1", "2", "5", "6"], }, index=[0, 1, 2, 3], )

My desired output should look like this

Answer 1

You can use df.stack() with Series.map and df.unstack:

In [95]: df3 = df1.set_index('user').stack().map(df2.set_index('N1')['N2']).unstack()

In [96]: df3
Out[96]: 
      p1 p2 p3 p4
user             
user1  1  2  1  6
user2  5  6  2  1
user3  6  6  5  2
user4  6  1  6  5