Best way to pretty print a hash

Question

I have a large hash with nested arrays and hashes   I would like to simply print it out so it  readable  to the user   I would like it to be sort of like to yaml - that s pretty readable - but still too tech looking     Ultimately its going to be end users who need to read these data chunks so they need to be formatted cleanly   Any suggestions

User · Answer

For large nested hashes this script could be helpful for you. It prints a nested hash in a nice python/like syntax with only indents to make it easy to copy.

module PrettyHash
  # Usage: PrettyHash.call(nested_hash)
  # Prints the nested hash in the easy to look on format
  # Returns the amount of all values in the nested hash

  def self.call(hash, level: 0, indent: 2)
    unique_values_count = 0
    hash.each do |k, v|
      (level * indent).times { print ' ' }
      print "#{k}:"
      if v.is_a?(Hash)
        puts
        unique_values_count += call(v, level: level + 1, indent: indent)
      else
        puts " #{v}"
        unique_values_count += 1
      end
    end
    unique_values_count
  end
end

Example usage:

  h = {a: { b: { c: :d }, e: :f }, g: :i }
  PrettyHash.call(h)

a:
  b:
    c: d
  e: f
g: i
=> 3

The returned value is the count (3) of all the end-level values of the nested hash.

User · Answer

If you don t have any fancy gem action  but do have JSON  this CLI line will work on a hash   puts JSON pretty generate my hash  gsub          gt        gt       key1   gt   value1       key2   gt   value2       key3   gt   value3

User · Answer

Easy to do with json if you trust your keys to be sane   JSON pretty generate a  1  2   gt  3  3   gt  nil     gsub    null      nil      gsub     s     a-zA-Z  a-zA-Z d            1  2        foo   1 - gt  foo  1   gsub     s                1  2   gt       123   1 - gt   123    gt  1      a  1     2    gt  3     3    gt  nil

User · Answer

I came here through a search engine looking for a way to print hashes to end users in a human-readable format   particularly hashes with underscores in their keys  Here s what I ended up doing using Rails 6 0 3 4  hash map do  key  val    key to s humanize          val to s end join          Turns   foo bar   gt   baz    fee ber   gt   bez  into  Foo bar  Baz  Fee ber  Bez

User · Answer

Of all the gems I tried  show data gem worked the best for me  I now use it extensively to log params hash in Rails pretty much all the time

User · Answer

In Rails If you need  a  quot pretty printed quot  Hash in e g  the Rails logger that  specifically  runs inspect on the objects in the Hash  which is useful if you override define the inspect method in your objects like you re supposed to        then this works great   And gets better  the bigger and more nested your Hash object is   logger error my hash pretty inspect  For example  class MyObject1   def inspect      quot  lt         10  My Object 1         10  gt  quot    end end  class MyObject2   def inspect      quot  lt         10  My Object 2         10  gt  quot    end end  my hash     a  1  b  MyObject1 new  MyObject2 new   gt  3    Rails logger error my hash     a  gt 1   b  gt  lt            My Object 1            gt    lt            My Object 2            gt   gt 3     EW     Rails logger error my hash pretty inspect     a  gt 1      b  gt  lt            My Object 1            gt       lt            My Object 2            gt   gt 3   pretty inspect comes from PrettyPrint  which rails includes by default  So  no gems needed and no conversion to JSON needed  Not In Rails If you re not in Rails or if the above fails for some reason  try using require  quot pp quot  first  For example  require  quot pp quot      lt -----------  class MyObject1   def inspect      quot  lt         10  My Object 1         10  gt  quot    end end  class MyObject2   def inspect      quot  lt         10  My Object 2         10  gt  quot    end end  my hash     a  1  b  MyObject1 new  MyObject2 new   gt  3    puts my hash     a  gt 1   b  gt  lt            My Object 1            gt    lt            My Object 2            gt   gt 3     EW     puts my hash pretty inspect     a  gt 1      b  gt  lt            My Object 1            gt       lt            My Object 2            gt   gt 3    A Full Example Big ol  pretty inspected Hash example from my project with project-specific text from my inspected objects redacted    lt                                                                                                                            -                       gt   gt      errors  gt        quot                                                                                                                                  quot         quot                                                                                                  is invalid quot         quot                                                            is invalid quot         quot                                      is invalid quot         quot                           is invalid quot         quot              is invalid quot                      gt         lt                                                                                                                  gt   gt                         gt              lt                                                                                      -               -   gt   gt                               lt                                                                                      -   gt   gt                               lt                                                                                            -   gt   gt                               lt                                                                                             -              gt   gt                               lt                                                                                           -   gt   gt                               lt                                                                                       -         gt   gt                               lt                                                                                      -                  -   gt   gt                             lt                                                                                                                            -       gt   gt           errors  gt             quot                                                                                                                     quot              quot                                                                                     is invalid quot              quot                                               is invalid quot              quot                         is invalid quot              quot              is invalid quot                           gt              lt                                                                                          -    -          gt   gt                               lt                                                                                          -    -          gt   gt                               lt                                                                                         -    -         gt   gt                               lt                                                                                           gt   gt                               lt                                                                                         -    -         gt   gt                               lt                                                                                         -    -           gt   gt                               lt                                                                                         -    -         gt   gt                errors  gt                  quot                                                                                                        quot                   quot                                                                        is invalid quot                   quot                                  is invalid quot                   quot            is invalid quot                                          gt                   lt                                                                      -                                                -                   -                       gt   gt                     errors  gt                       quot                                                                       quot                        quot                                       is invalid quot                                        gt                        lt                                                                                                         quot                           quot                 -                                                                                     quot        quot  - gt   quot  quot  gt   gt                          errors  gt   quot                                 quot                                        gt                            lt                                                      quot            quot    quot            quot    quot             quot    quot             quot    quot              quot    quot             quot    quot      quot        quot  quot       quot        quot  - gt   quot  quot  gt   gt                              errors  gt                                quot                      quot                                 quot                      quot                          lt                                                                                         -    -           gt   gt                               lt                                                                                         -    -           gt   gt                               lt                                                                                          -    -          gt   gt                               lt                                                                                          -    -            gt   gt                               lt                                                                                          -    -            gt   gt                               lt                                                                                          -    -            gt   gt

User · Answer

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

User · Answer

Under Rails  arrays and hashes in Ruby have built-in to json functions   I would use JSON just because it is very readable within a web browser  e g  Google Chrome   That being said if you are concerned about it looking too  tech looking  you should probably write your own function that replaces the curly braces and square braces in your hashes and arrays with white-space and other characters   Look up the gsub function for a very good way to do it   Keep playing around with different characters and different amounts of whitespace until you find something that looks appealing  http   ruby-doc org core-1 9 3 String html method-i-gsub

User · Answer

Here s another approach using json and rouge   require  json  require  rouge   formatter   Rouge  Formatters  Terminal256 new json lexer   Rouge  Lexers  JSON new  puts formatter format json lexer lex JSON pretty generate JSON parse response        parses response from e g  RestClient

User · Answer

If you have JSON  I recommend JSON pretty generate hash  because it is simpler than awesome print  looks great in a pre tag  and allows for easy copying from a web page   See also  How can I  quot pretty quot  format my JSON output in Ruby on Rails

User · Answer

Using Pry you just need to add the following code to your    pryrc   require  awesome print  AwesomePrint pry

User · Answer

Another solution which works better for me than pp or awesome print   require  pry    must install the gem    but you ALWAYS want pry installed anyways Pry  ColorPrinter pp obj

User · Answer

Use the answers above if you re printing to users   If you only want to print it for yourself in console  I suggest using the pry gem instead of irb  Besides pretty printing  pry has a lot of other features as well  check railscast below      gem install pry   And check this railscast   http   railscasts com episodes 280-pry-with-rails

[ruby] Best way to pretty print a hash

Example usage:

Examples related to ruby

Examples related to ruby-on-rails-3