class Array

The #scope method is called on an array of hashes. It returns a sub-array including only hashes for which the value at a given key is among the given values. The #scope method is non-destructive; the original array will remain intact after it is called. The #scope method is known to work for string or symbol keys. It should work for other data type keys as well.

Example:

array = [
  { name: 'Jean-Paul Sartre', nationality: 'French' },
  { name: 'Bertrand Russell', nationality: 'English' },
  { name: 'Ludwig Wittgenstein', nationality: 'Austrian' },
  { name: 'Albert Camus', nationality: 'French' }
]

array.scope(:nationality, 'French')
  # => [
         { name: 'Jean-Paul Sartre', nationality: 'French' },
         { name: 'Albert Camus', nationality: 'French' }
       ]

   # File lib/reactive_extensions/array/scope.rb
32 def scope(key, *values)
33   self.select {|hash| values.include? hash[key] }
34 end

The #subset_of? method checks whether the calling array is a subset of the given array. It returns true if all objects in the calling array are also present in the hash passed as an argument, regardless of order. If the calling array is empty, the method returns true.

Examples:

array = [1, 2, 3, 4]
[1, 3].subset_of? array                   # => true
[1, 6].subset_of? array                   # => false
[].subset_of? array                       # => true
array.subset_of? 'foobar'                 # => ArgumentError

   # File lib/reactive_extensions/object/sets.rb
57 def subset_of?(array)
58   raise ArgumentError.new("Argument of Array#subset_of? must be an array") unless array.instance_of? Array
59   each {|i| return false unless array.include? i }
60   true
61 end

The #superset_of? method checks whether the calling array is a superset of the given array. It returns true if all objects in the calling array are also present in the array passed as an argument. If the argument array is empty, the method returns true.

Examples:

array = [1, 2, 3, 4]
array.superset_of? [1, 2]                          # => true
array.superset_of? [1, 2, 3, 4]                    # => true
array.superset_of? [3, 6]                          # => false
array.superset_of? []                              # => true
array.superset_of? {}                              # => ArgumentError

   # File lib/reactive_extensions/object/sets.rb
76 def superset_of?(array)
77   raise ArgumentError.new("Argument of Array#superset_of? must be an array") unless array.instance_of? Array
78   array.subset_of? self
79 end

The #where_not method is called on an array of hashes. It returns a sub-array including only hashes for which the value at a given key is not among the given values. It is the inverse of the #scope method. The #where_not method is non-destructive; the original array will remain intact after it is called. The #where_not method is known to work for string or symbol keys. It should work for other data types as well.

Example:

array = [
  { name: 'Jean-Paul Sartre', nationality: 'French' },
  { name: 'Bertrand Russell', nationality: 'English' },
  { name: 'Ludwig Wittgenstein', nationality: 'Austrian' },
  { name: 'Albert Camus', nationality: 'French' }
]

array.where_not(:nationality, 'French')
  # => [
         { name: 'Bertrand Russell', nationality: 'English' },
         { name: 'Ludwig Wittgenstein', nationality: 'English' }
       ]

   # File lib/reactive_extensions/array/scope.rb
57 def where_not(key, *values)
58   self.reject {|hash| values.include? hash[key] }
59 end