Question

I have huge text file of such format:

aaa bbb 1      
aaa ccc 2      
aaa ddd 3      
bbb ww 1      
bbb kio 3      

I want to aggregate it and the result should be:

aaa bbb 1/6  
aaa ccc 2/6  
aaa ddd 3/6  
bbb ww 1/4  
bbb kio 3/4  

3rd column – probability p(y|x)

How should I do that using awk, sed?

Answer 1

awk 'NR==FNR{a[$1]+=$3;next}{printf("%s/%d\n",$0,a[$1])}' ./infile ./infile

Output

$ awk 'NR==FNR{a[$1]+=$3;next}{printf("%s/%d\n",$0,a[$1])}' ./infile ./infile
aaa bbb 1/6
aaa ccc 2/6
aaa ddd 3/6
bbb ww 1/4
bbb kio 3/4