Puppet Function: hash_select_re

Defined in:
puppet/modules/wmflib/lib/puppet/parser/functions/hash_select_re.rb
Function type:
Ruby 3.x API

Overview

hash_select_re() ⇒ Any

This function creates a new hash from the input hash, filtering out keys which do not match the provided regex.

Examples:

$in = { 'abc' => 1, 'def' => 2, 'asdf' => 3 }
$out = hash_select_re('^a', $in);
# $out == { 'abc' => 1, 'asdf' => 3 }
$out2 = hash_select_re('^(?!a)', $in);
# $out2 == { 'def' => 2 }

Returns:

  • (Any) 


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# File 'puppet/modules/wmflib/lib/puppet/parser/functions/hash_select_re.rb', line 6

newfunction(:hash_select_re, :type => :rvalue, :doc => <<-EOS
This function creates a new hash from the input hash, filtering out keys which
do not match the provided regex.

*Examples:*

  $in = { 'abc' => 1, 'def' => 2, 'asdf' => 3 }
  $out = hash_select_re('^a', $in);
  # $out == { 'abc' => 1, 'asdf' => 3 }
  $out2 = hash_select_re('^(?!a)', $in);
  # $out2 == { 'def' => 2 }

  EOS
) do |arguments|

  unless arguments.size == 2
    raise(Puppet::ParseError, "hash_select_re(): Wrong number of arguments " +
      "given (#{arguments.size} for 2)")
  end

  pattern = Regexp.new(arguments[0])
  in_hash = arguments[1]
  unless in_hash.is_a?(Hash)
    raise(Puppet::ParseError, 'hash_select_re(): Argument 2 must be a hash')
  end

  # https://bibwild.wordpress.com/2012/04/12/ruby-hash-select-1-8-7-and-1-9-3-simultaneously-compatible/
  Hash[ in_hash.select { |k, _v| pattern.match(k) } ]
end