Convert column to matrix format using awk

Question

I have a gridded data file in column format as:

ifile.txt
x     y     value
20.5  20.5  -4.1
21.5  20.5  -6.2
22.5  20.5   0.0
20.5  21.5   1.2
21.5  21.5   4.3
         


        

Answer 1

Perl solution:

#!/usr/bin/perl -an
$h{ $F[0] }{ $F[1] } = $F[2] unless 1 == $.;
END {
    @s = sort { $a <=> $b } keys %h;
    print ' ' x 5;
    printf '%5.1f' x @s, @s;
    print "\n";
    for my $u (@s) {
        print "$u ";
        printf '%5.1f', $h{$u}{$_} for @s;
        print "\n";
    }
}

• -n reads the input line by line
• -a splits each line on whitespace into the @F array
• See sort, print, printf, and keys.