Question

I am writing a awk script that takes some columns of input in a text file and print out the largest value in each column

Input:

 $cat numbers
    10      20      30.3    40.5
    20      30      45.7    66.1
    40      75      107.2   55.6
    50      20      30.3    40.5
    60      30      45.O    66.1
    70      1134.7  50      70
    80      75      107.2   55.6

Output:

80  1134.7  107.2       70

Script:

BEGIN {
val=0;
line=1;
}
{
if( $2 > $3 )
{
   if( $2 > val )
   {
      val=$2;
      line=$0;
   }
}
else
{
   if( $3 > val )
   {
      val=$3;
      line=$0;
   }
}
}
END{
print line
}

Current output:

 60 30  45.O    66.1

What am I doing wrong first awk script

=======SOLUTION======

 END {
  for (i = 0; ++i <= NF;)
   printf "%s", (m[i] (i < NF ? FS : RS))
   }
 {
 for (i = 0; ++i <= NF;)
   $i > m[i] && m[i] = $i
 }

Thanks for the help

Answer 1

You can create one user defined function and then pass individual column arrays to it to retrieve the max value. Something like this –

[jaypal:~/Temp] cat numbers
10 20 30.3 40.5
20 30 45.7 66.1
40 75 107.2 55.6
50 20 30.3 40.5
60 30 45.O 66.1
70 1134.7 50.0 70
80 75 107.2 55.6

[jaypal:~/Temp] awk '             
function max(x){i=0;for(val in x){if(i<=x[val]){i=x[val];}}return i;} 
{a[$1]=$1;b[$2]=$2;c[$3]=$3;d[$4]=$4;next} 
END{col1=max(a);col2=max(b);col3=max(c);col4=max(d);print col1,col2,col3,col4}' numbers
80 1134.7 107.2 70

or

awk 'a<$1{a=$1}b<$2{b=$2}c<$3{c=$3}d<$4{d=$4} END{print a,b,c,d}' numbers