File comparing and appending based on fields

Question

I want to compare 2 files, locus_file.txt is a very large file and atrr.txt is a small file. I want to match the first 2 columns of the first file to the second column of atrr.txt and print the attributes together.

locus_file.txt:large file

LOC_Os02g47020, LOC_Os03g57840,0.88725114
LOC_Os02g47020, LOC_Os07g36080,0.94455624
LOC_Os02g47020, LOC_Os03g02590,0.81881344

attr.txt: attribute file

blue LOC_Os02g47020
red  LOC_Os02g40830
blue LOC_Os07g36080
yellow LOC_Os03g57840
red LOC_Os03g02590

Desired output:

LOC_Os02g47020, LOC_Os03g57840,0.88725114,blue, yellow
LOC_Os02g47020, LOC_Os07g36080,0.94455624,blue, blue
LOC_Os02g47020, LOC_Os03g02590,0.81881344,blue, red

Note that: for example, In the first line of desired output, the 4th column has the color of LOC_Os02g47020 from atrr.txt and the 5th column has the color of LOC_Os03g57840 from atrr.txt

Answer 1

The task smells like a job for awk:

$ cat locus_file.txt 
LOC_Os02g47020, LOC_Os03g57840,0.88725114
LOC_Os02g47020, LOC_Os07g36080,0.94455624
LOC_Os02g47020, LOC_Os03g02590,0.81881344
$ cat attr.txt 
blue LOC_Os02g47020
red  LOC_Os02g40830
blue LOC_Os07g36080
yellow LOC_Os03g57840
red LOC_Os03g02590
$ awk 'BEGIN { while(getline<"attr.txt">0) c[$2]=$1 ; FS=",[ ]*" ; OFS=", " } { print $1,$2,$3,c[$1],c[$2] }' locus_file.txt 
LOC_Os02g47020, LOC_Os03g57840, 0.88725114, blue, yellow
LOC_Os02g47020, LOC_Os07g36080, 0.94455624, blue, blue
LOC_Os02g47020, LOC_Os03g02590, 0.81881344, blue, red

If you want "," instead of ", " or something different, just change OFS:

$ awk 'BEGIN { while(getline<"attr.txt">0) c[$2]=$1 ; FS=",[ ]*" ; OFS="," } { print $1,$2,$3,c[$1],c[$2] }' locus_file.txt 
LOC_Os02g47020,LOC_Os03g57840,0.88725114,blue,yellow
LOC_Os02g47020,LOC_Os07g36080,0.94455624,blue,blue
LOC_Os02g47020,LOC_Os03g02590,0.81881344,blue,red

Answer 2

An awk solution:

$ awk '
FNR == NR {a[$2] = $1;next}
{
    split($1,f1,",");
    split($2,f2,",");
    print $0,a[f1[1]],a[f2[1]];
}' OFS=, attr.txt locus_file.txt
LOC_Os02g47020, LOC_Os03g57840,0.88725114,blue,yellow
LOC_Os02g47020, LOC_Os07g36080,0.94455624,blue,blue
LOC_Os02g47020, LOC_Os03g02590,0.81881344,blue,red

Answer 3

How about something like

declare -A attr

while read x y; do attr[$y]="$x"; done < attr.txt

Then

while IFS=' ,' read a b c; do 
  d=${attr[$a]}
  e=${attr[$b]} 
  printf "%s, %s,%s,%s, %s\n" "$a" "$b" "$c" "$d" "$e"
done < locus_file.txt