How to Add Column with Percentage

Question

I would like to calculate percentage of value in each line out of all lines and add it as another column. Input (delimiter is \\t):

1   10      
2   10
3   20
4          


        

Answer 1

Perhaps there is better way but I would pass file twice.

Content of 'infile':

1       10 
2       10
3       20
4       40

Content of 'script.awk':

BEGIN {
        ## Tab as field separator.
        FS = "\t";
}

## First pass of input file. Get total from second field.
ARGIND == 1 {
        total += $2;
        next;
}

## Second pass of input file. Print each original line and percentage as third field.
{
        printf( "%s\t%2.2f\n", $0, $2 * 100 / total );
}

Run the script in my linux box:

gawk -f script.awk infile infile

And result:

1       10      12.50
2       10      12.50
3       20      25.00
4       40      50.00