Awk asking combine two files

I have combined two different files with Same Key by AWK command. And In case there is no key match compare to File1 and File2 then just put “ttt” instead.

I have below AWK command.

awk -F"t" '
{key = $1}
NR == 1 {header = key}
!(key in result) {result[key] = $0 ; next}
{ for (i=2; i <= NF; i++) result[key] = result[key] FS $i }
END {
    print result[header],"tValue2","tValue3","tValue4"
    delete result[header]
    PROCINFO["sorted_in"] = "@ind_str_asc"    # if using GNU awk
    for (key in result) print result[key]
}
' $1 $2 > $3

Example Combine File1

Key    Value1
 A     10000
 B     20000
 C     30000
 D     40000

File2

 B     50000      20000     10000   
 C     20000      10000     50000   

Then Expected result

Key    Value1    Value2    Value3    Value4
 A     10000       -         -         -
 B     20000     50000     20000     10000   
 C     30000     20000     10000    50000   
 D     40000       -         -         -

My AWK Command Show

Key    Value1    Value2    Value3    Value4
 A     10000       
 B     20000     50000     20000     10000   
 C     30000     20000     10000    50000   
 D     40000       

I already tried to do few way like below

!(key in result) {result[key] = $0"t-t-t-" ; next}

But looks like this is does not cover all cases. Anyone has better idea to do this? Thank you!

Answer

This solution doesn’t hardcode that there are 3 extra fields in File2

awk '
    BEGIN { FS = OVS = "t" }
    NR == FNR {
        key = $1
        $1 = ""
        store[key] = $0
        num_extra_fields = NF-1
        next
    } 
    FNR == 1 {
        printf "%s", $0
        for (i=1; i <= num_extra_fields; i++) 
            printf "%sValue%d", OFS, i+(NF-1)
        print ""
        next
    } 
    $1 in store {
        print $0  store[key]
        next
    } 
    { 
        for (i=1; i <= num_extra_fields; i++) 
            $(++NF)="-"
        print
    }
' file2 file1 

The output looks a bit odd due to how stackoverflow displays tabs

Key Value1  Value2  Value3  Value4
A   10000   -   -   -
B   20000   20000   10000   50000
C   30000   20000   10000   50000
D   40000   -   -   -

---

To fix your code, you need to keep track of the keys in file2 that update the results. Change

{ for (i=2; i <= NF; i++) result[key] = result[key] FS $i }

to

{ updated[key]=1; for (i=2; i <= NF; i++) result[key] = result[key] FS $i }

and, in the END block, change

  for (key in result) print result[key]

to

  for (key in result) {
    if (!(key in updated)) result[key] = result[key] FS "-" FS "-" FS "-"
    print result[key]
  }