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Included Modules

Hash

Public Class Methods

autonew(*args) click to toggle source

Hash which auto initializes it's children.

h = Hash.autonew
h['s1']['p1'] = 4
h['s1']['p2'] = 5
h['s1']['p3'] = 2
h['s1']['p4'] = 3

h #=> {"s1"=>{"p1"=>4, "p4"=>3, "p3"=>2, "p2"=>5}}

h['s1'].keys.sort
#=> ["p1", "p2", "p3", "p4"]

CREDIT: Trans, Jan Molic

# File lib/core/facets/hash/autonew.rb, line 18
def self.autonew(*args)
  leet = lambda{ |hsh, key| hsh[key] = new( &leet ) }
  new(*args,&leet)
end
new_with() click to toggle source

Instantiate a new hash with a default value determined by the block.

Hash.new_with{ [] }

CREDIT: Pit Capitan

# File lib/core/facets/hash/new_with.rb, line 10
def self.new_with #:yield:
  new { |h, k| h[k] = yield }
end
zip(keys,values) click to toggle source

Creates a new hash from two separate arrays, a keys array and a values array.

Hash.zip(["a","b","c"], [1,2,3])
# => { "a"=>1, "b"=>2, "c"=>3 }

CREDIT: Trans, Ara T. Howard

# File lib/core/facets/hash/zip.rb, line 11
def self.zip(keys,values) # or some better name
  h = {}
  keys.size.times{ |i| h[ keys[i] ] = values[i] }
  h
end

Public Instance Methods

&(other) click to toggle source

Hash intersection. Two hashes intersect when their pairs are equal.

({:a=>1,:b=>2} & {:a=>1,:c=>3})  #=> {:a=>1}

A hash can also be intersected with an array to intersect keys only.

({:a=>1,:b=>2} & [:a,:c])  #=> {:a=>1}

The later form is similar to pairs_at. The differ only in that pairs_at will return a nil value for a key not in the hash, but #& will not.

CREDIT: Trans

# File lib/core/facets/hash/op_and.rb, line 19
def &(other)
  case other
  when Array
    k = (keys & other)
    Hash[*(k.zip(values_at(*k)).flatten)]
  else
    x = (to_a & other.to_a).inject([]) do |a, kv|
      a.concat kv; a
    end
    Hash[*x]
  end
end
*(other) click to toggle source

Like merge operator ‘+’ but merges in reverse order.

h1 = {:a=>1}
h2 = {:a=>2, :b=>3}

(h1 + h2) #=> { :a=>2, :b=>3 }
(h1 * h2)  #=> { :a=>1, :b=>3 }

CREDIT: Trans

# File lib/core/facets/hash/op_mul.rb, line 13
def *(other)
  other.merge(self)
end
+(other) click to toggle source

Operator for merge.

CREDIT: Trans

# File lib/core/facets/hash/op_add.rb, line 7
def +(other)
  merge(other)
end
-(other) click to toggle source

Operator for remove hash paris. If another hash is given the pairs are only removed if both key and value are equal. If an array is given then matching keys are removed.

CREDIT: Trans CREDIT: Xavier Shay (bug fix)

# File lib/core/facets/hash/op_sub.rb, line 10
def -(other)
  h = self.dup
  if other.respond_to?(:to_ary)
    other.to_ary.each do |k|
      h.delete(k)
    end
  else
    other.each do |k,v|
      if h.key?(k)
        h.delete(k) if v == h[k]
      end
    end
  end
  h
end
<<(other) click to toggle source

Can be used like update, or passed as two-element [key,value] array.

CREDIT: Trans

# File lib/core/facets/hash/op_push.rb, line 8
def <<(other)
  if other.respond_to?(:to_ary)
    self.store(*other)
  else
    update(other)
  end
  self
end
alias!(newkey, oldkey) click to toggle source

Modifies the receiving Hash so that the value previously referred to by oldkey is also referenced by newkey; oldkey is retained in the Hash. If oldkey does not exist as a key in the Hash, no change is effected.

Returns a reference to the Hash.

foo = { :name=>'Gavin', 'wife'=>:Lisa }
foo.alias!('name',:name)     #=> { :name=>'Gavin', 'name'=>'Gavin', 'wife'=>:Lisa }

foo = { :name=>'Gavin', 'wife'=>:Lisa }
foo.alias!('spouse','wife')  #=> { :name=>'Gavin', 'wife'=>:Lisa, 'spouse'=>:Lisa }

foo = { :name=>'Gavin', 'wife'=>:Lisa }
foo.alias!('bar','foo')      #=> { :name=>'Gavin', 'wife'=>:Lisa }

Note that if the oldkey is reassigned, the reference will no longer exist, and the newkey will remain as it was.

CREDIT: Gavin Sinclair

TODO: Rename to aliaskey or something else.

# File lib/core/facets/hash/alias.rb, line 25
def alias!(newkey, oldkey)
  self[newkey] = self[oldkey] if self.has_key?(oldkey)
  self
end
argumentize(args_field=nil) click to toggle source

Turn a hash into a method arguments.

h = { :list => [1,2], :base => "HI" }

Without an argument field.

h.argumentize #=> [ { :list => [1,2], :base => "HI" } ]

With an argument field.

h.argumentize(:list)   #=> [ 1, 2, { :base => "HI" } ]
h.argumentize(:base)   #=> [ "HI", { :list => [1,2] } ]
# File lib/core/facets/hash/argumentize.rb, line 16
def argumentize(args_field=nil)
  config = dup
  if args_field
    args = [config.delete(args_field)].flatten.compact
  else
    args = []
  end
  args << config
  return args
end
collate(other) click to toggle source

Merge the values of this hash with those from another, setting all values to be arrays representing the values from both hashes.

{ :a=>1, :b=>2 }.collate(:a=>3, :b=>4, :c=>5)
#=> { :a=>[1,3], :b=>[2,4], :c=>[5] }

@author Trans (rewrite) @author Tilo Sloboda (bug fixes) @author Gavin Kistner (original)

# File lib/core/facets/hash/collate.rb, line 13
def collate(other)
  h = Hash.new
  (keys + other.keys).each do |key|
    h[key] = []
  end
  each do |key, value|
    h[key] << value
  end
  other.each do |key, value|
    h[key] << value
  end
  h.each{ |k,v| v.flatten! }
  h
end
collate!(other_hash) click to toggle source

The same as collate, but modifies the receiver in place.

# File lib/core/facets/hash/collate.rb, line 29
def collate!(other_hash)
  result = collate(other_hash)
  replace(result)
end
count(value) click to toggle source

Like Enumerable#count, but counts hash values.

{:A=>1, :B=>1}.count(1) #=> 2
# File lib/core/facets/hash/count.rb, line 7
def count(value)
  values.count(value)
end
data() click to toggle source

Access to a hash as if it were an OpenStruct.

h = {:a=>1, :b=>2}

h.data.a  #=> 1
h.data.b  #=> 2
h.data.c  #=> nil

h.data.c = 3
h.data.c  #=> 3

h.data.a?  #=> true
h.data.d?  #=> false

TODO: Change name of Hash#data to something better?

TODO: Is this really a method worth having?

# File lib/core/facets/hash/data.rb, line 22
def data
  this = self
  Functor.new do |op, *a|
    case op.to_s
    when /\=$/
      op = op.to_s.chomp('=')
      this[op] = a.first
    when /\?$/
      op = op.to_s.chomp('?')
      this.key?(op.to_s) || this.key?(op.to_sym)
    when /\!$/
      op = op.to_s.chomp('!')
      this[op] # ???
    else
      this[op.to_s] || this[op.to_sym]
    end
  end
end
dearray_singular_values() click to toggle source

Any array values with one or no elements will be set to the element or nil.

h = { :a=>[1], :b=>[1,2], :c=>3, :d=>[] }
h.dearray_singular_values  #=> { :a=>1, :b=>[1,2], :c=>3, :d=>nil }

CREDIT: Trans

# File lib/core/facets/hash/dearray_values.rb, line 32
def dearray_singular_values
  h = {}
  each do |k,v|
    case v
    when Array
      h[k] = (v.size < 2) ? v[0] : v
    else
      h[k] = v
    end
  end
  h
end
dearray_values(index=0) click to toggle source

Any array values with be replaced with the first element of the array. Arrays with no elements will be set to nil.

h = { :a=>[1], :b=>[1,2], :c=>3, :d=>[] }
h.dearray_values  #=> { :a=>1, :b=>1, :c=>3, :d=>nil }

CREDIT: Trans

# File lib/core/facets/hash/dearray_values.rb, line 11
def dearray_values(index=0)
  h = {}
  each do |k,v|
    case v
    when Array
      h[k] = v[index] || v[-1]
    else
      h[k] = v
    end
  end
  h
end
deep_merge(other) click to toggle source

Same as Hash#merge but recursively merges sub-hashes.

# File lib/core/facets/hash/deep_merge.rb, line 5
def deep_merge(other)
  hash = self.dup
  other.each do |key, value|
    myval = self[key]
    if value.is_a?(Hash) && myval.is_a?(Hash)
      hash[key] = myval.deep_merge(value)
    else
      hash[key] = value
    end
  end
  hash
end
deep_merge!(other) click to toggle source

Same as Hash#merge! but recursively merges sub-hashes.

# File lib/core/facets/hash/deep_merge.rb, line 20
def deep_merge!(other)
  other.each do |key, value|
    myval = self[key]
    if value.is_a?(Hash) && myval.is_a?(Hash)
      myval.deep_merge!(value)
    else
      self[key] = value
    end
  end
  self
end
delete_unless() click to toggle source

Inverse of delete_if.

h = { :a => 1, :b => 2, :c => 3 }
r = h.delete_unless{|k,v| v == 1}
r  #=> { :a => 1 }
h  #=> { :a => 1 }

CREDIT: Daniel Schierbeck

# File lib/core/facets/hash/delete_unless.rb, line 12
def delete_unless #:yield:
  delete_if{ |key, value| ! yield(key, value) }
end
delete_values(*values) click to toggle source

Minor modification to Ruby’s Hash#delete method allowing it to take multiple keys.

hsh = { :a => 1, :b => 2 }
hsh.delete_values(1)
hsh  #=> { :b => 2 }

Returns a list of keys of the deleted entries.

CREDIT: Daniel Schierbeck

# File lib/core/facets/hash/delete_values.rb, line 14
def delete_values(*values)
  deleted_keys = []
  keys.each do |key|
    if values.include?(fetch(key))
      deleted_keys << key
      delete(key)
    end
  end
  deleted_keys
end
delete_values_at(*keys, &yld) click to toggle source

Minor modification to Ruby’s Hash#delete method allowing it to take multiple keys.

hsh = {:a=>1, :b=>2, :c=>3}

a, b, c = hsh.delete_values_at(:a, :b, :c)

[a, b, c]  #=> [1, 2, 3]
hsh        #=> {}

CREDIT: Daniel Schierbeck

# File lib/core/facets/hash/delete_values.rb, line 37
def delete_values_at(*keys, &yld)
  keys.map{|key| delete(key, &yld) }
end
diff(hash) click to toggle source

Difference comparison of two hashes.

h1 = {:a=>1,:b=>2}
h2 = {:a=>1,:b=>3}

h1.diff(h2)  #=> {:b=>2}
h2.diff(h1)  #=> {:b=>3}
# File lib/core/facets/hash/diff.rb, line 11
def diff(hash)
  h1 = self.dup.delete_if{ |k,v| hash[k] == v }
  h2 = hash.dup.delete_if{ |k,v| has_key?(k) }
  h1.merge(h2)
end
each_with_key( &yld ) click to toggle source

Each with key is like each_pair but reverses the order the parameters to [value,key] instead of [key,value].

CREDIT: Trans

# File lib/core/facets/hash/keys.rb, line 40
def each_with_key( &yld )
  each_pair{ |k,v| yld.call(v,k) }
end
except(*less_keys) click to toggle source

Returns a new hash less the given keys.

# File lib/core/facets/hash/except.rb, line 4
def except(*less_keys)
  hash = dup
  less_keys.each{ |k| hash.delete(k) }
  hash
end
except!(*rejected) click to toggle source

Replaces hash with new hash less the given keys. This returns the hash of keys removed.

h = {:a=>1, :b=>2, :c=>3}
h.except!(:a)  #=> {:a=>1}
h              #=> {:b=>2,:c=>3}

Returns a Hash of the removed pairs.

# File lib/core/facets/hash/except.rb, line 18
def except!(*rejected)
  removed = {}
  rejected.each{ |k| removed[k] = delete(k) }
  removed
end
extractable_options?() click to toggle source

By default, only instances of Hash itself are extractable. Subclasses of Hash may implement this method and return true to declare themselves as extractable. If a Hash is extractable, Array#extract_options! pops it from the Array when it is the last element of the Array.

# File lib/core/facets/array/extract_options.rb, line 7
def extractable_options?
  instance_of?(Hash)
end
graph!(&yld) click to toggle source

In place version of graph.

NOTE: Hash#graph! is only useful for Hash. It is not generally applicable to Enumerable.

# File lib/core/facets/hash/graph.rb, line 10
def graph!(&yld)
  replace(graph(&yld))
end
Also aliased as: mash!
has_keys?(*check_keys) click to toggle source

Returns true or false whether the hash contains the given keys.

h = { :a => 1, :b => 2 }
h.has_keys?( :a )   #=> true
h.has_keys?( :c )   #=> false

CREDIT: Trans

# File lib/core/facets/hash/keys.rb, line 12
def has_keys?(*check_keys)
  unknown_keys = check_keys - self.keys
  return unknown_keys.empty?
end
Also aliased as: keys?
has_only_keys?(*check_keys) click to toggle source

Returns true if the hash contains only the given keys, otherwise false.

h = { :a => 1, :b => 2 }
h.has_only_keys?( :a, :b )   #=> true
h.has_only_keys?( :a )       #=> false

CREDIT: Trans

# File lib/core/facets/hash/keys.rb, line 28
def has_only_keys?(*check_keys)
  unknown_keys = self.keys - check_keys
  return unknown_keys.empty?
end
Also aliased as: only_keys?
insert(name, value) click to toggle source

As with store but only if the key isn’t already in the hash.

TODO: Would store? be a better name?

CREDIT: Trans

# File lib/core/facets/hash/insert.rb, line 10
def insert(name, value)
  if key?(name)
    false
  else
    store(name,value)
    true
  end
end
inverse() click to toggle source

Create a “true” inverse hash by storing mutliple values in Arrays.

h = {"a"=>3, "b"=>3, "c"=>3, "d"=>2, "e"=>9, "f"=>3, "g"=>9}

h.invert           #=> {2=>"d", 3=>"f", 9=>"g"}
h.inverse          #=> {2=>"d", 3=>["f", "c", "b", "a"], 9=>["g", "e"]}
h.inverse.inverse  #=> {"a"=>3, "b"=>3, "c"=>3, "d"=>2, "e"=>9, "f"=>3, "g"=>9}

Of course the inverse of the inverse should be the same.

(h.inverse.inverse == h)  #=> true

CREDIT: Tilo Sloboda

# File lib/core/facets/hash/inverse.rb, line 17
def inverse
  i = Hash.new
  self.each_pair{ |k,v|
    if (Array === v)
      v.each{ |x| i[x] = ( i.has_key?(x) ? [k,i[x]].flatten : k ) }
    else
      i[v] = ( i.has_key?(v) ? [k,i[v]].flatten : k )
    end
  }
  return i
end
join(pair_divider='', elem_divider=nil) click to toggle source

Like Array#join but specialized to Hash.

NOTE: Without Ruby 1.9 this would be difficult to rely on becuase hashes did not have a strict order.

CREDIT: Mauricio Fernandez

# File lib/core/facets/hash/join.rb, line 10
def join(pair_divider='', elem_divider=nil)
  elem_divider ||= pair_divider
  s = []
  each{ |k,v| s << "#{k}#{pair_divider}#{v}" }
  s.join(elem_divider)
end
keys?(*check_keys) click to toggle source
Alias for: has_keys?
mash!(&yld) click to toggle source

Alias for graph! as an alliteration for “map hash”.

Alias for: graph!
object_state(data=nil) click to toggle source
# File lib/core/facets/object/object_state.rb, line 61
def object_state(data=nil)
  data ? replace(data) : dup
end
only_keys?(*check_keys) click to toggle source
Alias for: has_only_keys?
recurse(*types, &block) click to toggle source

Apply a block to hash, and recursively apply that block to each sub-hash or types.

h = {:a=>1, :b=>{:b1=>1, :b2=>2}}
g = h.recurse{|h| h.inject({}){|h,(k,v)| h[k.to_s] = v; h} }
g  #=> {"a"=>1, "b"=>{"b1"=>1, "b2"=>2}}
# File lib/core/facets/hash/recurse.rb, line 10
def recurse(*types, &block)
  types = [self.class] if types.empty?
  h = inject({}) do |hash, (key, value)|
    case value
    when *types
      hash[key] = value.recurse(*types, &block)
    else
      hash[key] = value
    end
    hash
  end
  yield h
end
recurse!(&block) click to toggle source

In place form of recurse.

# File lib/core/facets/hash/recurse.rb, line 25
def recurse!(&block)
  replace(recurse(&block))
end
recursively(*types, &block) click to toggle source

Apply a block to a hash, and recursively apply that block to each sub-hash:

h = {:a=>1, :b=>{:x=>1, :y=>2}}
h.recursively.map{ |k,v| [k.to_s, v] }
#=> [["a", 1], ["b", [["y", 2], ["x", 1]]]]

The recursive iteration can be treated separately from the non-recursive iteration by passing a block to the recursive method:

h = {:a=>1, :b=>{:x=>1, :y=>2}}
h.recursively{ |k,v| [k.to_s, v] }.map{ |k,v| [k.to_s, v.to_s] }
#=> [["a", "1"], ["b", [["y", "2"], ["x", "1"]]]]
# File lib/core/facets/hash/recursively.rb, line 20
def recursively(*types, &block)
  Recursor.new(self, *types, &block)
end
rekey(key_map=nil, &block) click to toggle source

Rekey a hash:

rekey()
rekey(from_key => to_key, ...)
rekey{|from_key| to_key}

If a key map is given, then the first key is changed to the second key.

foo = { :a=>1, :b=>2 }
foo.rekey(:a=>'a')       #=> { 'a'=>1, :b=>2 }
foo.rekey(:b=>:x)        #=> { :a =>1, :x=>2 }
foo.rekey('foo'=>'bar')  #=> { :a =>1, :b=>2 }

If a block is given, converts all keys in the Hash accroding to the given block procedure. If the block returns NA for a given key, then that key will be left intact.

foo = { :name=>'Gavin', :wife=>:Lisa }
foo.rekey{ |k| k.to_s }  #=>  { "name"=>"Gavin", "wife"=>:Lisa }
foo                      #=>  { :name =>"Gavin", :wife=>:Lisa }

If no key map or block is given, then all keys are converted to Symbols.

Note that if both a key_map and a block are given, the key_map is applied first then the block.

CREDIT: Trans, Gavin Kistner

# File lib/core/facets/hash/rekey.rb, line 37
def rekey(key_map=nil, &block)
  if !(key_map or block)
    block = lambda{|k| k.to_sym}
  end

  key_map ||= {} 

  hash = dup.replace({})  # to keep default_proc

  (keys - key_map.keys).each do |key|
    hash[key] = self[key]
  end

  key_map.each do |from, to|
    hash[to] = self[from] if key?(from)
  end

  if block
    hash2 = dup.replace({})
    case block.arity
    when 2  # TODO: is this condition needed?
      hash.each do |k, v|
        nk = block.call(k,v)
        nk = (NA == nk ? k : nk)
        hash2[nk] = v
      end
    else
      hash.each do |k, v|
        nk = block.call(k)
        nk = (NA == nk ? k : nk)
        hash2[nk] = v
      end
    end
  else
    hash2 = hash
  end

  hash2
end
rekey!(key_map=nil, &block) click to toggle source

Synonym for Hash#rekey, but modifies the receiver in place (and returns it).

foo = { :name=>'Gavin', :wife=>:Lisa }
foo.rekey!{ |k| k.to_s }  #=>  { "name"=>"Gavin", "wife"=>:Lisa }
foo                       #=>  { "name"=>"Gavin", "wife"=>:Lisa }

CREDIT: Trans, Gavin Kistner

# File lib/core/facets/hash/rekey.rb, line 85
def rekey!(key_map=nil, &block)
  replace(rekey(key_map, &block))
end
replace_each() click to toggle source

Same as update_each, but deletes the key element first.

CREDIT: Trans

# File lib/core/facets/hash/replace_each.rb, line 7
def replace_each  # :yield:
  dup.each do |k,v|
    delete(k)
    update(yield(k,v))
  end
  self
end
reverse_merge(other) click to toggle source

Allows for reverse merging where its the keys in the calling hash that wins over those in the other_hash. This is particularly useful for initializing an incoming option hash with default values:

def setup(options = {})
  options.reverse_merge! :size => 25, :velocity => 10
end

The default :size and :velocity is only set if the options passed in doesn’t already have those keys set.

# File lib/core/facets/hash/reverse_merge.rb, line 15
def reverse_merge(other)
  other.merge(self)
end
reverse_merge!(other) click to toggle source

Inplace form of reverse_merge.

# File lib/core/facets/hash/reverse_merge.rb, line 21
def reverse_merge!(other)
  replace(reverse_merge(other))
end
Also aliased as: reverse_update
reverse_update(other) click to toggle source

Obvious alias for reverse_merge!

Alias for: reverse_merge!
select!() click to toggle source

In-place version of Hash#select. The opposite of the built-in Hash#reject!.

CREDIT: Gavin Sinclair, Noah Gibbs

# File lib/core/facets/hash/select.rb, line 10
def select!
  reject! { |k,v| not yield(k,v) }
end
shelljoin() click to toggle source
# File lib/standard/facets/shellwords.rb, line 107
def shelljoin
  shellwords.shelljoin
end
shellwords() click to toggle source
# File lib/standard/facets/shellwords.rb, line 87
def shellwords
  argv = []
  each do |f,v|
    m = f.to_s.size == 1 ? '-' : '--'
    case v
    when false, nil
    when Array
      v.each do |e|
        argv << %[#{m}#{f}="#{e}"]
      end
    when true
      argv << %[#{m}#{f}]
    else
      argv << %[#{m}#{f}="#{v}"]
    end
  end
  argv
end
slice(*keep_keys) click to toggle source

Returns a new hash with only the given keys.

h = {:a=>1, :b=>2}
h.slice(:a)  #=> {:a=>1}
# File lib/core/facets/hash/slice.rb, line 8
def slice(*keep_keys)
  hash = {}
  keep_keys.each do |key|
    hash[key] = fetch(key)
  end
  hash
end
slice!(*keep_keys) click to toggle source

Replaces hash with a new hash having only the given keys. This return the hash of keys removed.

h = {:a=>1, :b=>2}
h.slice!(:a)  #=> {:b=>2}
h             #=> {:a=>1}

Returns a Hash of the removed pairs.

# File lib/core/facets/hash/slice.rb, line 24
def slice!(*keep_keys)
  rejected = keys - keep_keys
  removed = {}
  rejected.each{ |k| removed[k] = delete(k) }
  removed
end
stringify_keys(&select) click to toggle source

Return a new hash with all keys converted to strings. Converts all keys in the Hash to Strings, returning a new Hash. With a select block, limits conversion to only a certain selection of keys.

foo = { :name=>'Gavin', :wife=>:Lisa }
foo.stringify_keys    #=>  { "name"=>"Gavin", "wife"=>:Lisa }
foo                   #=>  { :name =>"Gavin", :wife=>:Lisa }

This method is considered archaic. Use rekey instead.

# File lib/core/facets/hash/symbolize_keys.rb, line 61
def stringify_keys(&select)
  dup.stringify_keys!(&select)
end
stringify_keys!(&select) click to toggle source

Destructively convert all keys to strings. This is the same as Hash#stringify_keys, but modifies the receiver in place and returns it. With a select block, limits conversion to only certain keys.

foo = { :name=>'Gavin', :wife=>:Lisa }
foo.stringify_keys!    #=>  { "name"=>"Gavin", "wife"=>:Lisa }
foo                    #=>  { "name"=>"Gavin", "wife"=>:Lisa }

This method is considered archaic. Use rekey instead.

# File lib/core/facets/hash/symbolize_keys.rb, line 76
def stringify_keys!(&select)
  if select
    keys.each do |key|
      if select[key]
        self[key.to_s] = delete(key)
      end
    end
  else
    keys.each do |key|
      self[key.to_s] = delete(key)
    end
  end
  self
end
subset(keys=nil, &block) click to toggle source

Take a subset of the hash, based on keys given or a block that evaluates to true for each hash key.

{'a'=>1, 'b'=>2}.subset('a')            #=> {'a'=>1}
{'a'=>1, 'b'=>2}.subset{|k| k == 'a' }  #=> {'a'=>1}

CREDIT: Alexey Petrushin

# File lib/core/facets/hash/subset.rb, line 10
def subset(keys=nil, &block)
  h = {}
  if keys
    self.each do |k, v|
      h[k] = v if keys.include?(k)
    end
  else
    self.each do |k, v|
      h[k] = v if block.call(k)
    end
  end
  h
end
swap!(key1, key2) click to toggle source

Swap the values of a pair of keys in place.

{:a=>1,:b=>2}.swap!(:a,:b)  #=> {:a=>2,:b=>1}

CREDIT: Gavin Sinclair

# File lib/core/facets/hash/swap.rb, line 9
def swap!(key1, key2)
  tmp = self[key1]
  self[key1] = self[key2]
  self[key2] = tmp
  self
end
symbolize_keys(&select) click to toggle source

Return a new hash with all keys converted to symbols. With a select block, limits conversion to only a certain selection of keys.

foo = { :name=>'Gavin', 'wife'=>:Lisa }
foo.symbolize_keys    #=>  { :name=>"Gavin", :wife=>:Lisa }
foo                   #=>  { :name =>"Gavin", "wife"=>:Lisa }

If the key does not respond to to_sym, then to_s will be used first.

For a more versatile method, see rekey instead.

# File lib/core/facets/hash/symbolize_keys.rb, line 18
def symbolize_keys(&select)
  dup.symbolize_keys!(&select)
end
symbolize_keys!(&select) click to toggle source

Destructively convert all keys to symbols. This is the same as Hash#symbolize_keys, but modifies the receiver in place and returns it. With a select block, limits conversion to only selected keys.

foo = { 'name'=>'Gavin', 'wife'=>:Lisa }
foo.symbolize_keys!    #=>  { :name=>"Gavin", :wife=>:Lisa }
foo                    #=>  { :name=>"Gavin", :wife=>:Lisa }

If the key does not respond to to_sym, then to_s will be used first.

For a more versatile method, see rekey instead.

# File lib/core/facets/hash/symbolize_keys.rb, line 34
def symbolize_keys!(&select)
  if select
    keys.each do |key|
      if select[key]
        new_key = (key.to_sym rescue key.to_s.to_sym)
        self[new_key] = delete(key)
      end
    end       
  else
    keys.each do |key|
      new_key = (key.to_sym rescue key.to_s.to_sym)
      self[new_key] = delete(key)
    end
  end
  self
end
to_b() click to toggle source

Boolean conversion for not empty?

# File lib/core/facets/boolean.rb, line 117
def to_b
  ! self.empty?
end
to_h() click to toggle source

Return a rehashing of self.

{"a"=>1,"b"=>2}.to_h  #=> {"b"=>2,"a"=>1}

CREDIT: Forian Gross

# File lib/core/facets/to_hash.rb, line 211
def to_h; rehash; end
to_hash() click to toggle source

Returns self.

# File lib/core/facets/to_hash.rb, line 215
def to_hash; self; end
to_mod(&block) click to toggle source

Convert a hash into a module.

{:a=>1, :b=>2}.to_mod

Can take a block accepting key, value pairs which will be evaluated in the context of the module.

h = {:a=>1, :b=>2}
m = h.to_mod{ |k,v| module_function k }
m.a #=> 1
m.b #=> 2

CREDIT: Jay Fields

# File lib/core/facets/hash/to_mod.rb, line 20
def to_mod(&block)
  hash = self
  Module.new do
    hash.each do |key, value|
      define_method key do
        value #.to_object
      end
      instance_exec(key, value, &block) if block
    end
  end
end
to_ostruct() click to toggle source

Turns a hash into a generic object using an OpenStruct.

o = {'a' => 1}.to_ostruct
o.a  #=> 1
# File lib/standard/facets/ostruct.rb, line 172
def to_ostruct
  OpenStruct.new(self)
end
to_ostruct_recurse(exclude={}) click to toggle source

Like to_ostruct but recusively objectifies all hash elements as well.

o = {'a' => { 'b' => 1 }}.to_ostruct_recurse
o.a.b  #=> 1

The exclude parameter is used internally to prevent infinite recursion and is not intended to be utilized by the end-user. But for more advance use, if there is a particular subhash you would like to prevent from being converted to an OpoenStruct then include it in the exclude hash referencing itself. Eg.

h = { 'a' => { 'b' => 1 } }
o = h.to_ostruct_recurse( { h['a'] => h['a'] } )
o.a['b']  #=> 1

CREDIT: Alison Rowland, Jamie Macey, Mat Schaffer

# File lib/standard/facets/ostruct.rb, line 192
def to_ostruct_recurse(exclude={})
  return exclude[self] if exclude.key?( self )
  o = exclude[self] = OpenStruct.new
  h = self.dup
  each_pair do |k,v|
    h[k] = v.to_ostruct_recurse( exclude ) if v.respond_to?(:to_ostruct_recurse)
  end
  o.__update__(h)
end
to_proc(response=false) click to toggle source

Constructs a Proc object from a hash such that the parameter of the Proc is assigned the hash keys as attributes.

c = Class.new do
  attr_accessor :a
end

h = {:a => 1}
o = c.new
h.to_proc.call(o)
o.a  #=> 1

If response is set to true, then assignment will only occur if receiver responds_to? the writer method.

CREDIT: Trans

# File lib/core/facets/hash/to_proc.rb, line 20
def to_proc(response=false)
  if response
    lambda do |o|
      self.each do |k,v|
        ke = "#{k}="
        o.__send__(ke, v) if respond_to?(ke)
      end
    end
  else
    lambda do |o|
      self.each do |k,v|
        ke = "#{k}="
        o.__send__(ke, v)
      end
    end
  end
end
to_struct(struct_name) click to toggle source

A method to convert a Hash into a Struct.

h = {:name=>"Dan","age"=>33,"rank"=>"SrA","grade"=>"E4"}
s = h.to_struct("Foo")

TODO: Is this robust enough considerd hashes aren’t ordered?

CREDIT: Daniel Berger

# File lib/core/facets/hash/to_struct.rb, line 12
def to_struct(struct_name)
  Struct.new(struct_name,*keys).new(*values)
end
traverse(&block) click to toggle source

Returns a new hash created by traversing the hash and its subhashes, executing the given block on the key and value. The block should return a 2-element array of the form +[key, value]+.

h = {"A"=>"A", "B"=>"B", "C"=>{"X"=>"X"}}

g = h.traverse{ |k,v| [k.downcase, v] }

g  #=> {"a"=>"A", "b"=>"B", "c"=>{"x"=>"X"}}

NOTE: Hash#traverse is the same as `recursive.graph` and might be deprecated in the future (if it ever works!)

CREDIT: Trans

# File lib/core/facets/hash/traverse.rb, line 18
def traverse(&block)
  inject({}) do |h,(k,v)|
    if Hash === v
      v = v.traverse(&block)
    elsif v.respond_to?(:to_hash)
      v = v.to_hash.traverse(&block)
    end
    nk, nv = block.call(k,v)
    h[nk] = nv
    h
  end
end
traverse!(&block) click to toggle source

In place version of traverse, which traverses the hash and its subhashes, executing the given block on the key and value.

h = { "A"=>"A", "B"=>"B" }

h.traverse!{ |k,v| [k.downcase, v] }

h  #=> { "a"=>"A", "b"=>"B" }

CREDIT: Trans

# File lib/core/facets/hash/traverse.rb, line 42
def traverse!(&block)
  replace(traverse(&block))
end
update_each() click to toggle source

Iterates through each pair and updates a the hash in place. This is formally equivalent to mash! But does not use mash to accomplish the task. Hence update_each is probably a touch faster.

CREDIT: Trans

# File lib/core/facets/hash/update_each.rb, line 10
def update_each  # :yield:
  dup.each do |k,v|
   update(yield(k,v))
  end
  self
end
update_keys() click to toggle source

Iterate over hash updating just the keys.

h = {:a=>1, :b=>2}
h.update_keys{ |k| "#{k}!" }
h  #=> { "a!"=>1, "b!"=>2 }

@author Trans @author Evgeniy Dolzhenko (bug fix)

# File lib/core/facets/hash/update_keys.rb, line 12
def update_keys #:yield:
  if block_given?
    keys.each { |old_key| store(yield(old_key), delete(old_key)) }
  else
    to_enum(:update_keys)
  end
end
update_values() click to toggle source

Iterate over hash updating just the values.

h = {:a=>1, :b=>2}
h.update_values{ |v| v + 1 }
h  #=> { :a=>2, :b=>3 }

CREDIT: Trans

# File lib/core/facets/hash/update_values.rb, line 11
def update_values #:yield:
  if block_given?
    each{ |k,v| store(k, yield(v)) }
  else
    to_enum(:update_values)
  end
end
url_params() click to toggle source

Allows for taking a hash and turning it into CGI params Since 1.8.x does not have ordered hashes the params might not be ordered.

@todo Hash#url_params may require some URL escaping.

@author Matt Kirk

# File lib/core/facets/hash/url_params.rb, line 11
def url_params
  map do |k,v|
    if v.respond_to?(:join)
      "#{k}=#{v.join(",")}"
    else
      "#{k}=#{v}"
    end
  end.join("&")
end
weave(h) click to toggle source

Weave is a very uniqe hash operator. I is designed to merge to complex hashes in according to sensible, regular pattern. The effect is akin to inheritance.

Two hashes are weaved together to produce a new hash. The two hashes need to be compatible according to the following rules for each node: …

hash,   hash    => hash (recursive +)
hash,   array   => error
hash,   value   => error
array,  hash    => error
array,  array   => array + array
array,  value   => array << value
value,  hash    => error
value,  array   => array.unshift(valueB)
value1, value2  => value2

Here is a basic example:

h1 = { :a => 1, :b => [ 1 ], :c => { :x => 1 } }
h2 = { :a => 2, :b => [ 2 ], :c => { :x => 2 } }

h1.weave(h2)
#=> {:b=>[1, 2], :c=>{:x=>2}, :a=>2}

Weave follows the most expected pattern of unifying two complex hashes. It is especially useful for implementing overridable configuration schemes.

CREDIT: Thomas Sawyer

# File lib/core/facets/hash/weave.rb, line 35
def weave(h)
  raise ArgumentError, "Hash expected" unless h.kind_of?(Hash)
  s = self.clone
  h.each { |k,node|
    node_is_hash = node.kind_of?(Hash)
    node_is_array = node.kind_of?(Array)
    if s.has_key?(k)
      self_node_is_hash = s[k].kind_of?(Hash)
      self_node_is_array = s[k].kind_of?(Array)
      if self_node_is_hash
        if node_is_hash
          s[k] = s[k].weave(node)
        elsif node_is_array
          raise ArgumentError, 'Incompatible hash addition' #self[k] = node
        else
          raise ArgumentError, 'Incompatible hash addition' #self[k] = node
        end
      elsif self_node_is_array
        if node_is_hash
          raise ArgumentError, 'Incompatible hash addition' #self[k] = node
        elsif node_is_array
          s[k] += node
        else
          s[k] << node
        end
      else
        if node_is_hash
          raise ArgumentError, 'Incompatible hash addition' #self[k] = node
        elsif node_is_array
          s[k].unshift( node )
        else
          s[k] = node
        end
      end
    else
      s[k] = node
    end
  }
  s
end
|(other) click to toggle source

Operator for reverse_merge.

CREDIT: Trans

# File lib/core/facets/hash/op_or.rb, line 7
def |(other)
  other.merge(self)
end

[Validate]

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