finding the index based on two data frames of strings : One of my data look like this 

    O75663 	O95456 	O75663 	O95456 
    O95400 	O95670	O95400 	O95670
    O95433	        O95433	O95801 
    		        O95456 	P00352
    		        O95670	

My second data looks like this 

    O75663 
    O95400 
    O95433
    O95456 
    O95670
    O95801 
    P00352
    P00492


I want to know each string from second data is seen in which columns of the first data. it might never be seen or seen several time. I want the output to look like the following 

    strings    column ids 
    O75663      1, 3
    O95400      1, 3
    O95433      1, 3
    O95456      2, 3, 4
    O95670      2, 3, 4
    O95801      4
    P00352      4
    P00492      NA