replacing large amount of cells

Hello everyone.
I have a dataset which is a coauthorship network.Its data is like this:

1992,M_DINE,R_LEIGH,P_HUET,A_LINDE,D_LINDE
1992,C_BURGESS,J_CLINE,M_LUTY
1992,M_DINE,R_LEIGH,P_HUET,A_LINDE,D_LINDE
1992,F_ZWIRNER
1992,O_HERNANDEZ
...
It has about 38000 rows. I want to replace names of the authors with unique numbers so to do this I copied the names of the authors to another excel file, and now I want to replace the authors names(in the first file) with its row number in the second file. What should I do?Should I write a macro ?
It doesnot matter whether they are in one file or 2 seperate file.