Hi, Thank you for your answer. I want to do something slightly different now, and Im trying to do it with the code you provided, but since Im all new with this, the hashes and maps are a bit difficult to me.. I want to do it at a different order, because I want to do something else with it. I already combined multiple data files into one which now looks like this:

cg12045430 43 16 6 44 23 63 24 77
cg12045430 43 16 6 44 23 63 24 80
cg12045430 43 16 6 44 23 63 24 45
cg12045430 43 16 6 44 23 115 24 77
cg12045430 43 16 6 44 23 115 24 80
cg12045430 43 16 6 44 23 115 24 45
cg12045430 43 16 6 44 23 29 24 77
cg12045430 43 16 6 44 23 29 24 80
cg12045430 43 16 6 44 23 29 24 45
[download]

So I have again the same id's on multiple lines and different values on columns 2-9. I want for one ID get the average of columns 2-9. So for that input file that would be:

cg12045430 43 16 6 44 23 69 24 67
[download]

And afterwards I want to calculate the difference between column 2,3 and 4,5 and 6,7 and 8,9 like before. I tried to do it using your code and for every key calculate the average of the map, but it didn't work. Could you give me some advise? Thanks!