Psych.dump

(untyped o, ?indentation: ::Integer, ?line_width: ::Integer, ?canonical: bool, ?header: bool) -> ::String

[IO] (untyped o, IO, ?indentation: ::Integer, ?line_width: ::Integer, ?canonical: bool, ?header: bool) -> IO

Psych.dump(o) → string of yaml

Psych.dump(o, options) → string of yaml

Psych.dump(o, io) → io object passed in

Psych.dump(o, io, options) → io object passed in

ext/psych/lib/psych.rb View on GitHub ↗

# File tmp/rubies/ruby-3.4.1/ext/psych/lib/psych.rb, line 515
def self.dump o, io = nil, options = {}
  if Hash === io
    options = io
    io      = nil
  end

  visitor = Psych::Visitors::YAMLTree.create options
  visitor << o
  visitor.tree.yaml io, options
end

Dump Ruby object o to a YAML string. Optional options may be passed in to control the output format. If an IO object is passed in, the YAML will be dumped to that IO object.

Currently supported options are:

:indentation

Number of space characters used to indent. Acceptable value should be in 0..9 range, otherwise option is ignored.

Default: 2.

:line_width

Max character to wrap line at. For unlimited line width use -1.

Default: 0 (meaning “wrap at 81”).

:canonical

Write “canonical” YAML form (very verbose, yet strictly formal).

Default: false.

:header

Write %YAML [version] at the beginning of document.

Default: false.

:stringify_names

Dump symbol keys in Hash objects as string.

Default: false.

Example:

Example

# Dump an array, get back a YAML string
Psych.dump(['a', 'b'])  # => "---\n- a\n- b\n"

# Dump an array to an IO object
Psych.dump(['a', 'b'], StringIO.new)  # => #<StringIO:0x000001009d0890>

# Dump an array with indentation set
Psych.dump(['a', ['b']], indentation: 3) # => "---\n- a\n-  - b\n"

# Dump an array to an IO with indentation set
Psych.dump(['a', ['b']], StringIO.new, indentation: 3)

# Dump hash with symbol keys as string
Psych.dump({a: "b"}, stringify_names: true) # => "---\na: b\n"

See also .dump_stream .libyaml_version also in 4.1 · 4.0 · 3.3 · 3.2 · 3.1 · 3.0

next ›.dump_stream