Module: DaruLite::Vector::Filterable

Included in:
DaruLite::Vector
Defined in:
lib/daru_lite/vector/filterable.rb

Instance Method Summary collapse

Instance Method Details

#apply_where(bool_array) ⇒ DaruLite::Vector

Return a new vector based on the contents of a boolean array and &block.

Examples:

Usage of #apply_where.

dv = DaruLite::Vector.new ['3 days', '5 weeks', '2 weeks']
dv = dv.apply_where(dv.match /weeks/) { |x| "#{x.split.first.to_i * 7} days" }
# =>
##<DaruLite::Vector(3)>
#  0   3 days
#  1   35 days
#  2   14 days

Parameters:

  • bool_array (DaruLite::Core::Query::BoolArray, Array<TrueClass, FalseClass>, &block) —

    The collection containing the true of false values. Each element in the Vector corresponding to a ‘true` in the bool_array will be returned along with it’s index. The &block may contain manipulative functions for the Vector elements.

Returns:



61
62
63
 
# File 'lib/daru_lite/vector/filterable.rb', line 61

def apply_where(bool_array, &)
  DaruLite::Core::Query.vector_apply_where(self, bool_array, &)
end

#delete_if ⇒ Object

Delete an element if block returns true. Destructive.



74
75
76
77
78
79
80
81
82
83
84
85
 
# File 'lib/daru_lite/vector/filterable.rb', line 74

def delete_if
  return to_enum(:delete_if) unless block_given?

  keep_e, keep_i = each_with_index.reject { |n, _i| yield(n) }.transpose

  @data = cast_vector_to @dtype, keep_e
  @index = DaruLite::Index.new(keep_i)

  update_position_cache

  self
end

#keep_if ⇒ Object

Keep an element if block returns true. Destructive.



88
89
90
91
92
 
# File 'lib/daru_lite/vector/filterable.rb', line 88

def keep_if
  return to_enum(:keep_if) unless block_given?

  delete_if { |val| !yield(val) }
end

#only_numerics ⇒ Object

Returns a Vector with only numerical data. Missing data is included but non-Numeric objects are excluded. Preserves index.



118
119
120
121
122
123
124
125
 
# File 'lib/daru_lite/vector/filterable.rb', line 118

def only_numerics
  numeric_indexes =
    each_with_index
    .select { |v, _i| v.is_a?(Numeric) || v.nil? }
    .map(&:last)

  self[*numeric_indexes]
end

#reject_values(*values) ⇒ DaruLite::Vector

Return a vector with specified values removed

Examples:

dv = DaruLite::Vector.new [1, 2, nil, Float::NAN]
dv.reject_values nil, Float::NAN
# => #<DaruLite::Vector(2)>
#   0   1
#   1   2

Parameters:

  • values (Array) —

    values to reject from resultant vector

Returns:



103
104
105
106
107
108
109
110
111
112
113
114
 
# File 'lib/daru_lite/vector/filterable.rb', line 103

def reject_values(*values)
  resultant_pos = size.times.to_a - positions(*values)
  dv = at(*resultant_pos)
  # Handle the case when number of positions is 1
  # and hence #at doesn't return a vector
  if dv.is_a?(DaruLite::Vector)
    dv
  else
    pos = resultant_pos.first
    at(pos..pos)
  end
end

#uniq ⇒ Object

Keep only unique elements of the vector alongwith their indexes.



66
67
68
69
70
71
 
# File 'lib/daru_lite/vector/filterable.rb', line 66

def uniq
  uniq_vector = @data.uniq
  new_index   = uniq_vector.map { |element| index_of(element) }

  DaruLite::Vector.new uniq_vector, name: @name, index: new_index, dtype: @dtype
end

#where(bool_array) ⇒ Object

Return a new vector based on the contents of a boolean array. Use with the comparator methods to obtain meaningful results. See this notebook for a good overview of using #where.

Examples:

Usage of #where.

vector = DaruLite::Vector.new([2,4,5,51,5,16,2,5,3,2,1,5,2,5,2,1,56,234,6,21])

# Simple logic statement passed to #where.
vector.where(vector.eq(5).or(vector.eq(1)))
# =>
##<DaruLite::Vector:77626210 @name = nil @size = 7 >
#    nil
#  2   5
#  4   5
#  7   5
# 10   1
# 11   5
# 13   5
# 15   1

# A somewhat more complex logic statement
vector.where((vector.eq(5) | vector.lteq(1)) & vector.in([4,5,1]))
#=>
##<DaruLite::Vector:81072310 @name = nil @size = 7 >
#    nil
#  2   5
#  4   5
#  7   5
# 10   1
# 11   5
# 13   5
# 15   1

Parameters:

  • bool_array (DaruLite::Core::Query::BoolArray, Array<TrueClass, FalseClass>) —

    The collection containing the true of false values. Each element in the Vector corresponding to a ‘true` in the bool_arry will be returned alongwith it’s index.



40
41
42
 
# File 'lib/daru_lite/vector/filterable.rb', line 40

def where(bool_array)
  DaruLite::Core::Query.vector_where self, bool_array
end