intersecting to files by several columns using awk - bash

Question

I have two big CSV files that look like below:
f1.csv
f1_c1,f1_c2
A,B
C,A
B,D
f2.csv
f2_c1,f2_c2,f2_c3
chr1,fail,A
chr1,pass,B
chr1,neutral,C
chr2,fail,D
I want to intersect the two files in a way that the information from the first column and the second column of file two should be written for each row of f1 in separate columns. So based on what I mentioned the desired output should be as below:
f1_c1,f1_c2,f2_c1,f2_c1,f2_c2,f2_c2
A,B,chr1,chr1,fail,pass
C,A,chr1,chr1,neutral,fail
B,D,chr1,chr2,pass,fail
I have been trying to make this code work but it gives errors - would be great if you give some help to fix this.
awk 'BEGIN{FS=OFS=","}NR==FNR{gene[$3]=$1; type{$3]=$2; next}{ print ($1, $2, gene[$1], gene[$2], type[$1], type[$2] ) }' f2.csv f1.csv
Thank you.

Answer 1

You may use this awk:
awk 'BEGIN{FS=OFS=","} NR==1{print "f1_c1,f1_c2,f2_c1,f2_c1,f2_c2,f2_c2"} FNR==NR {m1[$3]=$1; m2[$3]=$2; next} FNR>1 {print $0, m1[$1], m1[$2], m2[$1], m2[$2]}' f2.csv f1.csv
f1_c1,f1_c2,f2_c1,f2_c1,f2_c2,f2_c2
A,B,chr1,chr1,fail,pass
C,A,chr1,chr1,neutral,fail
B,D,chr1,chr2,pass,fail
Expanded command:
awk '
BEGIN { FS = OFS = "," }
NR == 1 {
print "f1_c1,f1_c2,f2_c1,f2_c1,f2_c2,f2_c2"
}
FNR == NR {
m1[$3]=$1
m2[$3]=$2;
next
}
FNR > 1 {
print $0, m1[$1], m1[$2], m2[$1], m2[$2]
}' f2.csv f1.csv