Class: Arrow::TableFormatter

Inherits:
Object
  • Object
show all
Defined in:
lib/arrow/table-formatter.rb

Overview

TODO: Almost codes should be implemented in Apache Arrow C++.

Direct Known Subclasses

TableListFormatter, TableTableFormatter

Defined Under Namespace

Classes: ColumnFormatter

Instance Method Summary collapse

Constructor Details

#initialize(table, options = {}) ⇒ TableFormatter

Returns a new instance of TableFormatter.



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# File 'lib/arrow/table-formatter.rb', line 140

def initialize(table, options={})
  @table = table
  @options = options
end

Instance Method Details

#format ⇒ Object 



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# File 'lib/arrow/table-formatter.rb', line 145

def format
  text = ""
  n_rows = @table.n_rows
  border = @options[:border] || 10

  head_limit = [border, n_rows].min

  tail_start = [border, n_rows - border].max
  tail_limit = n_rows - tail_start

  column_formatters = @table.columns.collect do |column|
    head_values = column.each.take(head_limit)
    if tail_limit > 0
      tail_values = column.reverse_each.take(tail_limit).reverse
    else
      tail_values = []
    end
    ColumnFormatter.new(column, head_values, tail_values)
  end

  format_header(text, column_formatters)
  return text if n_rows.zero?

  n_digits = (Math.log10(n_rows) + 1).truncate
  format_rows(text,
              column_formatters,
              column_formatters.collect(&:head_values).transpose,
              n_digits,
              0)
  return text if n_rows <= border


  if head_limit != tail_start
    format_ellipsis(text)
  end

  format_rows(text,
              column_formatters,
              column_formatters.collect(&:tail_values).transpose,
              n_digits,
              tail_start)

  text
end