How to map dataframe based on two columns

[Mekala]

Hi,
I have two dataframes,

df1:

Name	Pop	RANK
Indian	333	1
USA	    42	56
Taiwan	688	3
Hsinchu	34	54
Indian	333	28
Taiwan	688	23

df2:

Name	CAP	  Pop	RANK
Indian	NDL	  333	1
USA	    WDC	  42	56
Taiwan	TPE	  688	3
Hsinchu	Zubei 34	54
Indian	NDL	  222	28

I want to map Name & RANK in df1 to df2, and get CAP from df2. I could only use one column mapping, but I could not be able to map based on two columns. I use below code,

df1['CAP'] = df1['Name','RANK'].map(df2.set_index(['Name','RANK'])['CAP']).fillna('')