Question

Often in Perl I want to print out column/row data, say, from a hash.

This is simple:

foreach my $k(keys %h)
{
  print $k, "\t", $h{$k}, "\n";
}

However, if the key happens to have a varying length, then the formatting just looks very jagged. I’ve investigated format, and it’s typically too heavyweight for what I’m looking for, which is a ‘simple’ column-row aligning pretty-printer.

Answer 1

I think you’ll find printf useful. Here is a small example:

printf("%10s\t%10s\n", $k, $h{$k});
## prints "         key\t         value\n"
## prints "  longer_key\t  longer_value\n"

Long values are not truncated, and you can change text alignment inside the block:

• %10s – means string type of length 10 (left aligned)
• %-10s – means string type of length 10 (right aligned)

A full list of formats is on the sprintf man page.