Formatting lists in tabular format

Question

# Comment: You can iterate through any number of Enumerables in lockstep
e = {
 numbers: 1..10,
 letters: %w(a b c d e f g h i j),
 notes: %w(do re mi fa so la ti do),
 phonetic: %w(alpha bravo charlie delta echo),
 rainbow: %w(red orange yellow green blue indigo violet)
}
# Titles
puts e.keys.map(&:capitalize).join(" ")
# Values
e.first[1].zip(*e.values[1..-1]) do |layer|
 layer.zip(e.keys) do |node|
 print node[0].to_s.rjust(node[1].length), " "
 end
 puts 
end

This code produces the following output:

Numbers Letters Notes Phonetic Rainbow
 1 a do alpha red 
 2 b re bravo orange 
 3 c mi charlie yellow 
 4 d fa delta green 
 5 e so echo blue 
 6 f la indigo 
 7 g ti violet 
 8 h do 
 9 i 
 10 j 

I want to tighten up that double loop at the bottom. Can I get rid of the puts that I am using to have each table row on its own line?

Answer 1

You code looks pretty good to me. Some notes:

• do |node| and then node[0], node[1]: You should unpack in the block: dp |val1, val2|

• Instead of mixing logic with I/O, first build the table string, then print it.

I'd write:

data = {
 numbers: 1..10,
 letters: %w(a b c d e f g h i j),
 notes: %w(do re mi fa so la ti do),
 phonetic: %w(alpha bravo charlie delta echo),
 rainbow: %w(red orange yellow green blue indigo violet)
}
header = data.keys.map { |k| k.to_s.capitalize }
table = data.values.first.zip(*data.values.drop(1)).map do |row|
 row.zip(header).map do |value, header_name|
 value.to_s.rjust(header_name.size)
 end.join(" ")
end
puts(([header.join(" ")] + table).join("\n"))