[R] Convert chr pieces to numbers that have specific values defined by 2 vectors

[tobias schlager]

Dear all, 

I think this is an easy task, but I don't know how to do it. Specifically, I have 69 columns with 300.000 rows. In each cell there is a code like 
"2E3", "4RR", etc.

I now have a list that replaces this with values, e.g., 
old	new
2E3 		5
4RR		3
etc. 

The list ist about 1600 rows long, so also to extensive for normal solutions

Do you how to do that? It would be great if you could help me, 
best, 
tobebryant