There must be a better way to do this:

    numstr = '17      75      -1      25      -1      52  43  37  0'
    => "17      75      -1      25      -1      52  43  37  0"
    numstr.sub(/(.{46})/) {|a| a.sub(/(..$)/) {|b| b.to_i + 3 }.to_s }
    => "17      75      -1      25      -1      52  46  37  0"

What is the better way?  (Note that in practice I'm using this to
operate on several strings in series, where each string has a number in
the same columnar position that needs to be incremented by three.)

-- 
Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ]