Sorting/counting a tab delimitated file

Question

I have a tab delimitated file with multiple columns. I'd like to extra the number of times I see something in column A and print the data associated with the value in column A in a new column B.

Ex:

1 blue                                        
1 green
1 red            
100 blue           
100 red

I'd like an output file that reads

3 1 blue,green,red
2 100 blue,red

Is there away to do this using awk or perl?

Answer 1

in awk:

{
  if (count[$1] == "") {
    count[$1] = 1;
    results[$1] = $2;
  } else {
    count[$1] = count[$1] + 1;
    results[$1] = results[$1] "," $2;
  }
}
END {
  for (number in count) {
    print count[number],number,results[number];
  }
}

results in the output of: 2 100 blue,red 3 1 blue,green,red

for your sample data above.

The order of the results may not be quite what you want, I'm not sure how critical that is for you.

Answer 2

Here is what I have tried that may work for you. NOTE: "\011" = tab char, change to " " for space)

awk 'BEGIN { s = "\011"; c = "," ; cnt = 0; all_colors = "" } {
    if ( NR == 1 ) { num = $1; colors[cnt++] = $2 }
    else {
        if ( num != $1 ) {
            for (x=0; x<cnt; x++) {
                all_colors = all_colors colors[x]
                }
            print cnt s num s all_colors; cnt = 0; all_colors = ""
            num = $1; colors[cnt++] = $2
            }
        else { colors[cnt++] = c $2 }
        }
    }
END {
    all_colors = ""
    for (x=0; x<cnt; x++) { all_colors = all_colors colors[x] }
    print cnt s num s all_colors
}' tab_file

   tab_file                output
1       blue          3       1       blue,green,red
1       green         2       100     blue,red
1       red
100     blue
100     red