Module: DaruLite::DataFrame::Indexable

Included in:
DaruLite::DataFrame
Defined in:
lib/daru_lite/data_frame/indexable.rb

Defined Under Namespace

Modules: SetCategoricalIndexStrategy, SetMultiIndexStrategy, SetSingleIndexStrategy

Instance Method Summary collapse

Instance Method Details

#index=(idx) ⇒ Object

Reassign index with a new index of type DaruLite::Index or any of its subclasses.

Examples:

Reassigining index of a DataFrame

df = DaruLite::DataFrame.new({a: [1,2,3,4], b: [11,22,33,44]})
df.index.to_a #=> [0,1,2,3]

df.index = DaruLite::Index.new(['a','b','c','d'])
df.index.to_a #=> ['a','b','c','d']
df.row['a'].to_a #=> [1,11]

Parameters:

  • idx (DaruLite::Index) —

    New index object on which the rows of the dataframe are to be indexed.



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# File 'lib/daru_lite/data_frame/indexable.rb', line 123

def index=(idx)
  @index = Index.coerce idx
  @data.each { |vec| vec.index = @index }

  self
end

#reindex(new_index) ⇒ Object

Change the index of the DataFrame and preserve the labels of the previous indexing. New index can be DaruLite::Index or any of its subclasses.

Examples:

Reindexing DataFrame

df = DaruLite::DataFrame.new({a: [1,2,3,4], b: [11,22,33,44]},
  index: ['a','b','c','d'])
#=>
##<DaruLite::DataFrame:83278130 @name = b19277b8-c548-41da-ad9a-2ad8c060e273 @size = 4>
#                    a          b
#         a          1         11
#         b          2         22
#         c          3         33
#         d          4         44
df.reindex DaruLite::Index.new(['b', 0, 'a', 'g'])
#=>
##<DaruLite::DataFrame:83177070 @name = b19277b8-c548-41da-ad9a-2ad8c060e273 @size = 4>
#                    a          b
#         b          2         22
#         0        nil        nil
#         a          1         11
#         g        nil        nil

Parameters:

  • new_index (DaruLite::Index) —

    The new Index for reindexing the DataFrame.



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# File 'lib/daru_lite/data_frame/indexable.rb', line 87

def reindex(new_index)
  unless new_index.is_a?(DaruLite::Index)
    raise ArgumentError, 'Must pass the new index of type Index or its ' \
                         "subclasses, not #{new_index.class}"
  end

  cl = DaruLite::DataFrame.new({}, order: @vectors, index: new_index, name: @name)
  new_index.each_with_object(cl) do |idx, memo|
    memo.row[idx] = @index.include?(idx) ? row[idx] : Array.new(ncols)
  end
end

#reindex_vectors(new_vectors) ⇒ Object 



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# File 'lib/daru_lite/data_frame/indexable.rb', line 130

def reindex_vectors(new_vectors)
  unless new_vectors.is_a?(DaruLite::Index)
    raise ArgumentError, 'Must pass the new index of type Index or its ' \
                         "subclasses, not #{new_vectors.class}"
  end

  cl = DaruLite::DataFrame.new({}, order: new_vectors, index: @index, name: @name)
  new_vectors.each_with_object(cl) do |vec, memo|
    memo[vec] = @vectors.include?(vec) ? self[vec] : Array.new(nrows)
  end
end

#reset_index ⇒ Object 



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# File 'lib/daru_lite/data_frame/indexable.rb', line 99

def reset_index
  index_df = index.to_df
  names = index.name
  names = [names] unless names.instance_of?(Array)
  new_vectors = names + vectors.to_a
  self.index = index_df.index
  names.each do |name|
    self[name] = index_df[name]
  end
  self.order = new_vectors
  self
end

#set_index(new_index_col, keep: false, categorical: false) ⇒ Object

Set a particular column as the new DF



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# File 'lib/daru_lite/data_frame/indexable.rb', line 45

def set_index(new_index_col, keep: false, categorical: false)
  if categorical
    strategy = SetCategoricalIndexStrategy
  elsif new_index_col.respond_to?(:to_a)
    strategy = SetMultiIndexStrategy
    new_index_col = new_index_col.to_a
  else
    strategy = SetSingleIndexStrategy
  end

  unless categorical
    uniq_size = strategy.uniq_size(self, new_index_col)
    raise ArgumentError, 'All elements in new index must be unique.' if @size != uniq_size
  end

  self.index = strategy.new_index(self, new_index_col)
  strategy.delete_vector(self, new_index_col) unless keep
  self
end

#vectors=(new_index) ⇒ Object

Reassign vectors with a new index of type DaruLite::Index or any of its subclasses.

Examples:

Reassigning vectors of a DataFrame

df = DaruLite::DataFrame.new({a: [1,2,3,4], b: [:a,:b,:c,:d], c: [11,22,33,44]})
df.vectors.to_a #=> [:a, :b, :c]

df.vectors = DaruLite::Index.new([:foo, :bar, :baz])
df.vectors.to_a #=> [:foo, :bar, :baz]

Parameters:

  • new_index (DaruLite::Index) —

    idx The new index object on which the vectors are to be indexed. Must of the same size as ncols.

Raises:

  • (ArgumentError) 


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# File 'lib/daru_lite/data_frame/indexable.rb', line 152

def vectors=(new_index)
  raise ArgumentError, 'Can only reindex with Index and its subclasses' unless new_index.is_a?(DaruLite::Index)

  if new_index.size != ncols
    raise ArgumentError, "Specified index length #{new_index.size} not equal to" \
                        "dataframe size #{ncols}"
  end

  @vectors = new_index
  @data.zip(new_index.to_a).each do |vect, name|
    vect.name = name
  end
  self
end