Ruby: How to Make Irb Print Structure for Arrays and Hashes

Ruby: How to make IRB print structure for Arrays and Hashes

You can either use the inspect method:

a=["value1", "value2", "value3"]
puts a.inspect

Or, even better, use the pp (pretty print) lib:

require 'pp'
a=["value1", "value2", "value3"]
pp a

Best way to pretty print a hash

require 'pp'
pp my_hash

Use pp if you need a built-in solution and just want reasonable line breaks.

Use awesome_print if you can install a gem. (Depending on your users, you may wish to use the index:false option to turn off displaying array indices.)

Printing array of arrays, each internal on separate line

Use Kernel#p rather than Kernel#puts.

('a'..'c').to_a.combination(2).each { |a| p a }
["a", "b"]
["a", "c"]
["b", "c"]

Note that, while Array#combination without a block returns an enumerator, you don't have to convert it to an array before each'ing it.

IRB and large variables?

Or, can I print each one on a separate line, tabbed-in depending on depth?

Use pp (pretty print):

require 'pp'
very_long_hash = Hash[(1..23).zip(20..42)]
pp very_long_hash
# Prints:
{1=>20,
 2=>21,
 3=>22,
 4=>23,
 5=>24,
 6=>25,
 7=>26,
 8=>27,
 9=>28,
 10=>29,
 11=>30,
 12=>31,
 13=>32,
 14=>33,
 15=>34,
 16=>35,
 17=>36,
 18=>37,
 19=>38,
 20=>39,
 21=>40,
 22=>41,
 23=>42}

How do you print Ruby hashes as arrays? I keep getting hex values

The issue isn't that you're not using a hash correctly, it's that you are printing out the Game object. You may need to make your own method to grab the exact attributes you would like printed. For example

def print_assists(game)
  puts game.RawStatsDto.assists
end

It is also worth noting that when printing objects for debugging purposes, it is almost always better to use p instead of puts e.g. p game

search through an array of hashes and print out result

You can do something like this

@email = "thomas@fake.nl"
user = @users.find {|u| u[:email] == @email}
if user
  puts "Welcome #{user[:name]}"
else
  puts "Your account does not exist try again!"
end

Hash inspection in IRB?

Object.inspect

The method is usually used for printing object structure.

IRB (apparently) not inspecting hashes correctly

The issue here is that invoking h["test"] doesn't actually insert a new key into the hash - it just returns the default value, which is the array that you passed to Hash.new.

1.8.7 :010 > a = []
 => []
1.8.7 :011 > a.object_id
 => 70338238506580
1.8.7 :012 > h = Hash.new(a)
 => {}
1.8.7 :013 > h["test"].object_id
 => 70338238506580
1.8.7 :014 > h["test"] << "blah"
 => ["blah"]
1.8.7 :015 > h.keys
 => []
1.8.7 :016 > h["bogus"]
 => ["blah"]
1.8.7 :017 > h["bogus"].object_id
 => 70338238506580
1.8.7 :019 > a
 => ["blah"]

The hash itself is still empty - you haven't assigned anything to it. The data isn't present in the hash - it's present in the array that is returned for missing keys in the hash.

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