Compare three columns of two files

Question

I have two files that have some similar and some unique columns. I'd like to compare the first 3 columns that are similar and print if they match, along with each of their unique columns.

File1:

A cat pizza 34 24 56 
A dog tomato 304 959 030
B bird grape 4.4 939 33
C snake broccoli 89 28 273 

File2:

A cat pizza 55 85 328
B dog tomato 404 56 32
C snake sandwich 384 34 75

Which should make

File3:

A cat pizza 34 24 56 55 85 328

I've been trying

awk  'NR==FNR       {c[$1$2$3]++;next}
      c[$1$2$3] > 0 {print $0}'

but I'm not getting any matches.

Answer 1

I'd do something like

function join(start, end, sep,       str, i) {
    if (!sep) sep = OFS
    str = $start
    for (i = start + 1; i <= end; i++) str = str sep $i
    return str
}
 
          { key = $1 OFS $2 OFS $3 }
NR == FNR { f1[key] = join(4, NF); next }
key in f1 { print key, f1[key], join(4, NF) }

Run with

awk -f script.awk file1 file2