Ruby – Is it possible to specify formatting options for to_yaml in ruby


The code

require 'yaml'
puts YAML.load("
  values: ['yes', 'no']


  - "yes"
  - "no"

While this is a correct yaml, it just looks ugly when you have a hash of arrays. Is there a way for me to get to_yaml to produce the inline array version of the yaml?

An options hash can be passed to to_yaml but how do you use it?

Edit 0: Thanks Pozsár Balázs. But, as of ruby 1.8.7 (2009-04-08 patchlevel 160), the options hash does not work as advertised. 🙁

irb(main):001:0> require 'yaml'
=> true
irb(main):002:0> puts [[ 'Crispin', 'Glover' ]].to_yaml( :Indent => 4, :UseHeader => true, :UseVersion => true )
- - Crispin
  - Glover
=> nil

Best Solution

About the hash options: see

Ex. 24: Using to_yaml with an options Hash

puts [[ 'Crispin', 'Glover' ]].to_yaml( :Indent => 4, :UseHeader => true, :UseVersion => true )
# prints:
#   --- %YAML:1.0
#   -
#       - Crispin
#       - Glover

Ex. 25: Available symbols for an options Hash

Indent: The default indentation to use when emitting (defaults to 2)
Separator: The default separator to use between documents (defaults to '---')
SortKeys: Sort Hash keys when emitting? (defaults to false)
UseHeader: Display the YAML header when emitting? (defaults to false)
UseVersion: Display the YAML version when emitting? (defaults to false)
AnchorFormat: A formatting string for anchor IDs when emitting (defaults to 'id%03d')
ExplicitTypes: Use explicit types when emitting? (defaults to false)
BestWidth: The character width to use when folding text (defaults to 80)
UseFold: Force folding of text when emitting? (defaults to false)
UseBlock: Force all text to be literal when emitting? (defaults to false)
Encoding: Unicode format to encode with (defaults to :Utf8; requires Iconv)