combine files consisting of two columns

Question

I have multiple files that look like this:

file1:

rsRNA-2312-n    2
rsRNA-6508-n    2
rsRNA-6382-n    10
rsRNA-951-n 0
rsRNA-6330-n    4
rsRNA-6330-         


        

Answer 1

Another solution ....

awk '
{ d[$1][FILENAME] = $2 }
END{
    line = "identifier";
    for (i=1; i in ARGV; i++) line = line OFS ARGV[i];
    print line
    for(i in d){
        line = i;
        for (j=1; j in ARGV; j++){
            if(ARGV[j] in d[i]) line = line OFS d[i][ARGV[j]]
            else line = line OFS 0
        }
        print line
    }
}' file1 file2 file3

you get:

identifier file1 file2 file3
rsRNA-946-n 9 0 0
rsRNA-4945-n 0 7 0
rsRNA-1385-n 3 0 0
rsRNA-2312-n 2 0 0
rsRNA-6382-n 10 0 0
rsRNA-951-n 0 0 0
rsRNA-6490-n 0 2 0
rsRNA-6330-n 11 0 0
rsRNA-5301-n 0 7 0
rsRNA-5058-n 0 0 0
rsRNA-4946-n 0 0 1
rsRNA-2445-n 0 9 0
rsRNA-552-n 0 2 1
rsRNA-6487-n 0 0 0
rsRNA-4099-n 0 0 0
rsRNA-849-n 0 0 2
rsRNA-3302-n 0 0 2
rsRNA-6508-n 2 0 0