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

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 21

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 26

def format
  text = ""
  columns = @table.columns
  format_header(text, columns)

  n_rows = @table.n_rows
  return text if n_rows.zero?

  border = @options[:border] || 10
  n_digits = (Math.log10(n_rows) + 1).truncate
  head_limit = [border, n_rows].min
  head_column_values = columns.collect do |column|
    column.each.take(head_limit)
  end
  format_rows(text,
              columns,
              head_column_values.transpose,
              n_digits,
              0)
  return text if n_rows <= border

  tail_start = [border, n_rows - border].max
  tail_limit = n_rows - tail_start
  tail_column_values = columns.collect do |column|
    column.reverse_each.take(tail_limit).reverse
  end

  if head_limit != tail_start
    format_ellipsis(text)
  end

  format_rows(text,
              columns,
              tail_column_values.transpose,
              n_digits,
              tail_start)

  text
end