Class: Rust::DataFrame

Inherits:
RustDatatype show all
Defined in:
lib/rust/core/types/dataframe.rb

Overview

Mirror of the data-frame type in R.

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from RustDatatype

#r_hash, #r_mirror, #r_mirror_to

Constructor Details

#initialize(labels_or_data) ⇒ DataFrame

Creates a new data-frame. labels_or_data can be either:

  • an Array of column names (creates an empty data-frame)

  • a Hash with column names as keys and values as values



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# File 'lib/rust/core/types/dataframe.rb', line 32

def initialize(labels_or_data)
    @data = {}
    
    if labels_or_data.is_a? Array
        @labels = labels_or_data.map { |l| l.to_s }
        @labels.each { |label| @data[label] = [] }
    elsif labels_or_data.is_a? Hash
        @labels = labels_or_data.keys.map { |l| l.to_s }
        
        labels_or_data.each do |key, value|
            @data[key.to_s] = value.clone
        end
    end
end

Class Method Details

.can_pull?(type, klass) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rust/core/types/dataframe.rb', line 9

def self.can_pull?(type, klass)
    return [klass].flatten.include?("data.frame")
end

.pull_priority ⇒ Object 



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# File 'lib/rust/core/types/dataframe.rb', line 13

def self.pull_priority
    1
end

.pull_variable(variable, type, klass) ⇒ Object 



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# File 'lib/rust/core/types/dataframe.rb', line 17

def self.pull_variable(variable, type, klass)
    hash = {}
    colnames = Rust["colnames(#{variable})"]
    colnames.each do |col|
        hash[col] = Rust["#{variable}$\"#{col}\""]
    end
    return DataFrame.new(hash)
end

Instance Method Details

#[](rows, cols = nil) ⇒ Object

Returns a copy of the data-frame containing only the specified rows and/or cols. If rows and/or cols are nil, all the rows/columns are returned.



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# File 'lib/rust/core/types/dataframe.rb', line 90

def [](rows, cols=nil)
    raise "You must specify either rows or columns to select" if !rows && !cols
    result = self
    if rows && (rows.is_a?(Range) || rows.is_a?(Array))
        result = result.select_rows { |row, i| rows.include?(i) }
    end
    
    if cols && cols.is_a?(Array)
        cols = cols.map { |c| c.to_s }
        result = result.select_columns(cols)
    end
    
    return result
end

#add_column(name, values = nil) ⇒ Object

Adds a column named name with the given values (array). The size of values must match the number of rows of this data-frame. As an alternative, it can be passed a block which returns, for a given row, the value to assign for the new column.



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# File 'lib/rust/core/types/dataframe.rb', line 285

def add_column(name, values=nil)
    raise "Column already exists" if @labels.include?(name)
    raise "Values or block required" if !values && !block_given?
    raise "Number of values not matching" if values && values.size != self.rows
    
    @labels << name
    if values
        @data[name] = values.clone
    else
        @data[name] = []
        self.each_with_index do |row, i|
            @data[name][i] = yield row
        end
    end
end

#add_row(row) ⇒ Object Also known as: <<

Adds the given row to the data-frame. row can be either:

  • An Array of values for all the columns (in the order of #column_names);

  • A Hash containing associations between column names and value to be set.



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# File 'lib/rust/core/types/dataframe.rb', line 257

def add_row(row)
    if row.is_a?(Array)
        raise "Expected an array of size #{@data.size}" unless row.size == @data.size
        
        @labels.each_with_index do |label, i|
            @data[label] << row[i]
        end
        
        return true
    elsif row.is_a?(Hash)
        raise "Expected a hash with the following keys: #{@data.keys}" unless row.keys.map { |l| l.to_s }.sort == @data.keys.sort
        
        row.each do |key, value|
            @data[key.to_s] << value
        end
        
        return true
    else
        raise TypeError, "Expected an Array or a Hash"
    end
end

#aggregate(by, **aggregators) ⇒ Object

Aggregate the value in groups depending on the by column (String). A block must be passed to specify how to aggregate the columns. Aggregators for specific columns can be specified as optional arguments in which the name of the argument represents the column name and the value contains a block for aggregating the specific column. Both the default and the specialized blocks must take as argument an array of values and must return a scalar value.

Raises:

  • (TypeError) 


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# File 'lib/rust/core/types/dataframe.rb', line 490

def aggregate(by, **aggregators)
    raise TypeError, "Expected a string" unless by.is_a?(String)
    raise TypeError, "All the aggregators should be procs" unless aggregators.values.all? { |v| v.is_a?(Proc) }
    raise "Expected a block for default aggregator" unless block_given?
    
    aggregators = aggregators.map { |label, callable| [label.to_s, callable] }.to_h
    
    sorted = self.sort_by(by)
    
    current_value = nil
    partials = []
    partial = nil
    sorted.column(by).each_with_index do |value, index|
        if current_value != value
            current_value = value
            partials << partial if partial
            partial = Rust::DataFrame.new(self.column_names)
        end
        partial << sorted.fast_row(index)
    end
    partials << partial
    
    result = Rust::DataFrame.new(self.column_names)
    partials.each do |partial|
        aggregated_row = {}
        aggregated_row[by] = partial.column(by)[0]
        (self.column_names - [by]).each do |column|
            if aggregators[column]
                aggregated_row[column] = aggregators[column].call(partial.column(column))
            else
                aggregated_row[column] = yield partial.column(column)
            end
        end
        
        result << aggregated_row
    end
    
    return result
end

#bind_columns(dataframe) ⇒ Object Also known as: cbind

Returns a copy of this dataframe and adds all the columns in dataframe to it. The number of rows must match.



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# File 'lib/rust/core/types/dataframe.rb', line 611

def bind_columns(dataframe)
    result = self.clone
    result.bind_columns!(dataframe)
    return result
end

#bind_columns!(dataframe) ⇒ Object Also known as: cbind!

Adds all the columns in dataframe to this data-frame. The number of rows must match.

Raises:

  • (TypeError) 


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# File 'lib/rust/core/types/dataframe.rb', line 585

def bind_columns!(dataframe)
    raise TypeError, "DataFrame expected" unless dataframe.is_a?(DataFrame)
    raise "The number of rows are not compatible" if self.rows != dataframe.rows
    raise "The dataset would override some columns" if (self.column_names & dataframe.column_names).size > 0
    
    dataframe.column_names.each do |column_name|
        self.add_column(column_name, dataframe.column(column_name))
    end
    
    return true
end

#bind_rows(dataframe) ⇒ Object Also known as: rbind

Returns a copy of this dataframe and adds all the rows in dataframe to it. The column names must match.



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# File 'lib/rust/core/types/dataframe.rb', line 601

def bind_rows(dataframe)
    result = self.clone
    result.bind_rows!(dataframe)
    return result
end

#bind_rows!(dataframe) ⇒ Object Also known as: rbind!

Adds all the rows in dataframe to this data-frame. The column names must match.

Raises:

  • (TypeError) 


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# File 'lib/rust/core/types/dataframe.rb', line 570

def bind_rows!(dataframe)
    raise TypeError, "DataFrame expected" unless dataframe.is_a?(DataFrame)
    raise "The columns are not compatible: #{self.column_names - dataframe.column_names} - #{dataframe.column_names - self.column_names}" unless (self.column_names & dataframe.column_names).size == self.columns
    
    dataframe.each do |row|
        self << row
    end
    
    return true
end

#clone ⇒ Object

Returns a copy of this data-frame.



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# File 'lib/rust/core/types/dataframe.rb', line 621

def clone
    DataFrame.new(@data)
end

#column(name) ⇒ Object Also known as: |

Return the column named name.



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# File 'lib/rust/core/types/dataframe.rb', line 108

def column(name)
    return @data[name]
end

#column_names ⇒ Object Also known as: colnames

Return the names of the columns.



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# File 'lib/rust/core/types/dataframe.rb', line 233

def column_names
    return @labels.map { |k| k.to_s }
end

#columns ⇒ Object

Returns the number of columns



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# File 'lib/rust/core/types/dataframe.rb', line 248

def columns
    @labels.size
end

#delete_column(column) ⇒ Object

Deletes the column named column.



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# File 'lib/rust/core/types/dataframe.rb', line 182

def delete_column(column)
    @labels.delete(column)
    @data.delete(column)
end

#delete_row(i) ⇒ Object

Deletes the i-th row.



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# File 'lib/rust/core/types/dataframe.rb', line 190

def delete_row(i)
    @data.each do |label, column|
        column.delete_at(i)
    end
end

#each ⇒ Object

Yields each row as a Hash containing column names as keys and values as values.



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# File 'lib/rust/core/types/dataframe.rb', line 304

def each
    self.each_with_index do |element, i|
        yield element
    end
    
    return self
end

#each_with_index ⇒ Object

Yields each row as a Hash containing column names as keys and values as values and the row index.



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# File 'lib/rust/core/types/dataframe.rb', line 327

def each_with_index
    for i in 0...self.rows
        element = {}
        @labels.each do |label|
            element[label] = @data[label][i]
        end
        
        yield element, i
    end
    
    return self
end

#fast_each ⇒ Object

Yields each row as a Hash containing column names as keys and values as values. Faster alternative to #each.



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# File 'lib/rust/core/types/dataframe.rb', line 316

def fast_each
    self.fast_each_with_index do |element, i|
        yield element
    end
    
    return self
end

#fast_each_with_index ⇒ Object

Yields each row as a Hash containing column names as keys and values as values and the row index. Faster alternative to #each_with_index.



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# File 'lib/rust/core/types/dataframe.rb', line 344

def fast_each_with_index
    for i in 0...self.rows
        element = []
        @labels.each do |label|
            element << @data[label][i]
        end
        
        yield element, i
    end
    
    return self
end

#fast_row(i) ⇒ Object

Returns the i-th row of the data-frame. Faster (but harder to interpret) alternative to #row.



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# File 'lib/rust/core/types/dataframe.rb', line 61

def fast_row(i)
    if i < 0 || i >= self.rows
        return nil
    else
        return @labels.map { |label| @data[label][i] }
    end
end

#has_row? ⇒ Boolean

Returns true if the function given in the block returns true for any of the rows in this data-frame.

Returns:

  • (Boolean) 


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# File 'lib/rust/core/types/dataframe.rb', line 153

def has_row?
    self.each_with_index do |row, i|
        return true if yield row, i
    end
    return false
end

#head(n = 10) ⇒ Object

Returns a copy of the data-frame containing only the first n rows.



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# File 'lib/rust/core/types/dataframe.rb', line 403

def head(n=10)
    result = DataFrame.new(self.column_names)
    self.each_with_index do |row, i|
        result << row if i < n
    end
    return result
end

#inspect ⇒ Object 



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# File 'lib/rust/core/types/dataframe.rb', line 379

def inspect
    separator = " | "
    col_widths = self.column_names.map { |colname| [colname, ([colname.length] + @data[colname].map { |e| e.inspect.length }).max] }.to_h
    col_widths[:rowscol] = (self.rows - 1).inspect.length + 3
    
    result = ""
    result << "-" * (col_widths.values.sum + ((col_widths.size - 1) * separator.length)) + "\n"
    result << (" " * col_widths[:rowscol]) + self.column_names.map { |colname| (" " * (col_widths[colname] - colname.length)) + colname }.join(separator) + "\n"
    result << "-" * (col_widths.values.sum + ((col_widths.size - 1) * separator.length)) + "\n"
    self.each_with_index do |row, i|
        index_part = "[" + (" " * (col_widths[:rowscol] - i.inspect.length - 3)) + "#{i}] "
        row_part   = row.map { |colname, value| (" " * (col_widths[colname] - value.inspect.length)) + value.inspect }.join(separator)
        
        result << index_part + row_part + "\n"
    end
    
    result << "-" * (col_widths.values.sum + ((col_widths.size - 1) * separator.length))
    
    return result
end

#load_in_r_as(variable_name) ⇒ Object 



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# File 'lib/rust/core/types/dataframe.rb', line 357

def load_in_r_as(variable_name)
    command = []
    
    command << "#{variable_name} <- data.frame()"
    row_index = 1
    self.each do |row|
        command << "#{variable_name}[#{row_index.to_R}, #{row.keys.to_R}] <- #{row.values.to_R}"
        
        row_index += 1
    end
    
    self.column_names.each do |name|
        column = self.column(name)
        
        if column.is_a?(Factor)
            command << "#{variable_name}[,#{name.to_R}] <- factor(#{variable_name}[,#{name.to_R}], labels=#{column.levels.to_R})"
        end
    end
    
    Rust._eval_big(command)
end

#merge(other, by, first_alias = "x", second_alias = "y") ⇒ Object

Merges this data-frame with other in terms of the by column(s) (Array or String). first_alias and second_alias allow to specify the prefix that should be used for the columns not in by for this and the other data-frame, respectively.

Raises:

  • (TypeError) 


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# File 'lib/rust/core/types/dataframe.rb', line 416

def merge(other, by, first_alias = "x", second_alias = "y")
    raise TypeError, "Expected Rust::DataFrame" unless other.is_a?(DataFrame)
    raise TypeError, "Expected list of strings" if !by.is_a?(Array) || !by.all? { |e| e.is_a?(String) }
    raise "This dataset should have all the columns in #{by}" unless (by & self.column_names).size == by.size
    raise "The passed dataset should have all the columns in #{by}" unless (by & other.column_names).size == by.size
    
    if first_alias == second_alias
        if first_alias == ""
            my_columns = self.column_names - by
            other_columns = other.column_names - by
            intersection = my_columns & other_columns
            raise "Cannot merge because the following columns would overlap: #{intersection}" if intersection.size > 0
        else
            raise "The aliases can not have the same value"
        end
    end
    
    my_keys = {}
    self.each_with_index do |row, i|
        key = []
        by.each do |colname|
            key << row[colname]
        end
        
        my_keys[key] = i
    end
    
    merged_column_self  = (self.column_names - by)
    merged_column_other = (other.column_names - by)
    
    first_alias =  first_alias + "."     if first_alias.length > 0
    second_alias = second_alias + "."    if second_alias.length > 0
    
    merged_columns = merged_column_self.map { |colname| "#{first_alias}#{colname}" } + merged_column_other.map { |colname| "#{second_alias}#{colname}" }
    columns = by + merged_columns
    result = DataFrame.new(columns)
    other.each do |other_row|
        key = []
        by.each do |colname|
            key << other_row[colname]
        end
        
        my_row_index = my_keys[key]
        if my_row_index
            my_row = self.row(my_row_index)
            
            to_add = {}
            by.each do |colname|
                to_add[colname] = my_row[colname]
            end
            
            merged_column_self.each do |colname|
                to_add["#{first_alias}#{colname}"] = my_row[colname]
            end
            
            merged_column_other.each do |colname|
                to_add["#{second_alias}#{colname}"] = other_row[colname]
            end
            
            result << to_add
        end
    end
    
    return result
end

#rename_column!(old_name, new_name) ⇒ Object

Renames the column named old_name in new_name.



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# File 'lib/rust/core/types/dataframe.rb', line 116

def rename_column!(old_name, new_name)
    raise "This DataFrame does not contain a column named #{old_name}" unless @labels.include?(old_name)
    raise "This DataFrame already contains a column named #{new_name}" if @labels.include?(new_name)
    
    @data[new_name.to_s] = @data.delete(old_name)
    @labels[@labels.index(old_name)] = new_name
end

#row(i) ⇒ Object

Returns the i-th row of the data-frame



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# File 'lib/rust/core/types/dataframe.rb', line 50

def row(i)
    if i < 0 || i >= self.rows
        return nil
    else
        return @data.map { |label, values| [label, values[i]] }.to_h
    end
end

#rows ⇒ Object

Returns the number of rows.



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# File 'lib/rust/core/types/dataframe.rb', line 241

def rows
    @data.values[0].size
end

#select_columns(cols = nil) ⇒ Object Also known as: select_cols

Returns a copy of the data-frame with only the columns in cols. As an alternative, a block can be used (only the columns for which the function returns true are kept).



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# File 'lib/rust/core/types/dataframe.rb', line 164

def select_columns(cols=nil)
    raise "You must specify either the columns you want to select or a selection block" if !cols && !block_given?
    
    result = self.clone
    @labels.each do |label|
        if cols
            result.delete_column(label) unless cols.include?(label)
        else
            result.delete_column(label) unless yield label
        end
    end
    return result
end

#select_rows ⇒ Object

Returns a copy data-frame with only the rows for which the function given in the block returns true. Example: df = Rust::DataFrame.new([1,2,3], b: [‘a’,‘b’,‘c’]) df2 = df.select_rows { |r| r.even? } df2|“b” # => [‘b’]



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# File 'lib/rust/core/types/dataframe.rb', line 142

def select_rows
    result = DataFrame.new(self.column_names)
    self.each_with_index do |row, i|
        result << row if yield row, i
    end
    return result
end

#shuffle(*args) ⇒ Object

Shuffles the rows in the data-frame. The arguments are passed to the Array#shuffle method.



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# File 'lib/rust/core/types/dataframe.rb', line 72

def shuffle(*args)
    result = DataFrame.new(@labels)
    
    buffer = []
    self.each do |row|
        buffer << row
    end
    buffer.shuffle!(*args).each do |row|
        result << row
    end
    
    return result
end

#sort_by(column) ⇒ Object

Returns a copy of this data-frame in which the rows are sorted by the values of the by column.



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# File 'lib/rust/core/types/dataframe.rb', line 533

def sort_by(column)
    result = self.clone
    result.sort_by!(column)
    return result
end

#sort_by!(by) ⇒ Object

Sorts the rows of this data-frame by the values of the by column.



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# File 'lib/rust/core/types/dataframe.rb', line 542

def sort_by!(by)
    copy = @data[by].clone
    copy.sort!
    
    indices = []
    @data[by].each_with_index do |value, i|
        index = copy.index(value)
        indices << index
        
        copy[index] = NilClass
    end
                
    (self.column_names - [by]).each do |column_name|
        sorted = []
        column = self.column(column_name)
        column_i = 0
        indices.each do |i|
            sorted[i] = column[column_i]
            column_i += 1
        end
        @data[column_name] = sorted
    end
    @data[by].sort!
end

#transform_column!(column) ⇒ Object

Functionally transforms the column named column by applying the function given as a block. Example: df = Rust::DataFrame.new([1,2,3], b: [3,4,5]) df.transform_column!(“a”) { |v| v + 1 } df|“a” # => [2, 3, 4]



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# File 'lib/rust/core/types/dataframe.rb', line 131

def transform_column!(column)
    @data[column].map! { |e| yield e }
end

#uniq_by(by) ⇒ Object

Returns a data-frame in which the rows are unique in terms of all the given columns named by.



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# File 'lib/rust/core/types/dataframe.rb', line 199

def uniq_by(by)
    result = self.clone
    result.uniq_by!(by)
    return result
end

#uniq_by!(by) ⇒ Object

Makes sure that in this data-frame the rows are unique in terms of all the given columns named by.



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# File 'lib/rust/core/types/dataframe.rb', line 208

def uniq_by!(by)
    my_keys = {}
    to_delete = []
    self.each_with_index do |row, i|
        key = []
        by.each do |colname|
            key << row[colname]
        end
        unless my_keys[key]
            my_keys[key] = i
        else
            to_delete << (i-to_delete.size)
        end
    end
    
    to_delete.each do |i|
        self.delete_row(i)
    end
    
    return self
end