A CSV::Table is a two-dimensional data structure for representing CSV documents. Tables allow you to work with the data by row or column, manipulate the data, and even convert the results back to CSV, if needed.

All tables returned by CSV will be constructed from this class, if header row processing is activated.

Methods
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Included Modules
Attributes
[R] mode

The current access mode for indexing and iteration.
[R] table

Internal data format used to compare equality.
Class Public methods
new(array_of_rows)

Construct a new CSV::Table from array_of_rows, which are expected to be CSV::Row objects. All rows are assumed to have the same headers.

A CSV::Table object supports the following Array methods through delegation:

  • empty?()

  • length()

  • size()

Source: show | on GitHub 

# File lib/csv.rb, line 575
def initialize(array_of_rows)
  @table = array_of_rows
  @mode  = :col_or_row
end
Instance Public methods
<<(row_or_array)

Adds a new row to the bottom end of this table. You can provide an Array, which will be converted to a CSV::Row (inheriting the table's headers()), or a CSV::Row.

This method returns the table for chaining.

Source: show | on GitHub 

# File lib/csv.rb, line 773
def <<(row_or_array)
  if row_or_array.is_a? Array  # append Array
    @table << Row.new(headers, row_or_array)
  else                         # append Row
    @table << row_or_array
  end

  self  # for chaining
end
==(other)

Returns true if all rows of this table ==() other's rows.

Source: show | on GitHub 

# File lib/csv.rb, line 852
def ==(other)
  @table == other.table
end
[](index_or_header)

In the default mixed mode, this method returns rows for index access and columns for header access. You can force the index association by first calling #by_col!() or #by_row!().

Columns are returned as an Array of values. Altering that Array has no effect on the table.

Source: show | on GitHub 

# File lib/csv.rb, line 689
def [](index_or_header)
  if @mode == :row or  # by index
     (@mode == :col_or_row and index_or_header.is_a? Integer)
    @table[index_or_header]
  else                 # by header
    @table.map { |row| row[index_or_header] }
  end
end
[]=(index_or_header, value)

In the default mixed mode, this method assigns rows for index access and columns for header access. You can force the index association by first calling #by_col!() or #by_row!().

Rows may be set to an Array of values (which will inherit the table's headers()) or a CSV::Row.

Columns may be set to a single value, which is copied to each row of the column, or an Array of values. Arrays of values are assigned to rows top to bottom in row major order. Excess values are ignored and if the Array does not have a value for each row the extra rows will receive a nil.

Assigning to an existing column or row clobbers the data. Assigning to new columns creates them at the right end of the table.

Source: show | on GitHub 

# File lib/csv.rb, line 714
def []=(index_or_header, value)
  if @mode == :row or  # by index
     (@mode == :col_or_row and index_or_header.is_a? Integer)
    if value.is_a? Array
      @table[index_or_header] = Row.new(headers, value)
    else
      @table[index_or_header] = value
    end
  else                 # set column
    if value.is_a? Array  # multiple values
      @table.each_with_index do |row, i|
        if row.header_row?
          row[index_or_header] = index_or_header
        else
          row[index_or_header] = value[i]
        end
      end
    else                  # repeated value
      @table.each do |row|
        if row.header_row?
          row[index_or_header] = index_or_header
        else
          row[index_or_header] = value
        end
      end
    end
  end
end
by_col()

Returns a duplicate table object, in column mode. This is handy for chaining in a single call without changing the table mode, but be aware that this method can consume a fair amount of memory for bigger data sets.

This method returns the duplicate table for chaining. Don't chain destructive methods (like []=()) this way though, since you are working with a duplicate.

Source: show | on GitHub 

# File lib/csv.rb, line 601
def by_col
  self.class.new(@table.dup).by_col!
end
by_col!()

Switches the mode of this table to column mode. All calls to indexing and iteration methods will work with columns until the mode is changed again.

This method returns the table and is safe to chain.

Source: show | on GitHub 

# File lib/csv.rb, line 611
def by_col!
  @mode = :col

  self
end
by_col_or_row()

Returns a duplicate table object, in mixed mode. This is handy for chaining in a single call without changing the table mode, but be aware that this method can consume a fair amount of memory for bigger data sets.

This method returns the duplicate table for chaining. Don't chain destructive methods (like []=()) this way though, since you are working with a duplicate.

Source: show | on GitHub 

# File lib/csv.rb, line 626
def by_col_or_row
  self.class.new(@table.dup).by_col_or_row!
end
by_col_or_row!()

Switches the mode of this table to mixed mode. All calls to indexing and iteration methods will use the default intelligent indexing system until the mode is changed again. In mixed mode an index is assumed to be a row reference while anything else is assumed to be column access by headers.

This method returns the table and is safe to chain.

Source: show | on GitHub 

# File lib/csv.rb, line 638
def by_col_or_row!
  @mode = :col_or_row

  self
end
by_row()

Returns a duplicate table object, in row mode. This is handy for chaining in a single call without changing the table mode, but be aware that this method can consume a fair amount of memory for bigger data sets.

This method returns the duplicate table for chaining. Don't chain destructive methods (like []=()) this way though, since you are working with a duplicate.

Source: show | on GitHub 

# File lib/csv.rb, line 653
def by_row
  self.class.new(@table.dup).by_row!
end
by_row!()

Switches the mode of this table to row mode. All calls to indexing and iteration methods will work with rows until the mode is changed again.

This method returns the table and is safe to chain.

Source: show | on GitHub 

# File lib/csv.rb, line 663
def by_row!
  @mode = :row

  self
end
delete(index_or_header)

Removes and returns the indicated column or row. In the default mixed mode indices refer to rows and everything else is assumed to be a column header. Use #by_col!() or #by_row!() to force the lookup.

Source: show | on GitHub 

# File lib/csv.rb, line 801
def delete(index_or_header)
  if @mode == :row or  # by index
     (@mode == :col_or_row and index_or_header.is_a? Integer)
    @table.delete_at(index_or_header)
  else                 # by header
    @table.map { |row| row.delete(index_or_header).last }
  end
end
delete_if(&block)

Removes any column or row for which the block returns true. In the default mixed mode or row mode, iteration is the standard row major walking of rows. In column mode, interation will yield two element tuples containing the column name and an Array of values for that column.

This method returns the table for chaining.

Source: show | on GitHub 

# File lib/csv.rb, line 818
def delete_if(&block)
  if @mode == :row or @mode == :col_or_row  # by index
    @table.delete_if(&block)
  else                                      # by header
    to_delete = Array.new
    headers.each_with_index do |header, i|
      to_delete << header if block[[header, self[header]]]
    end
    to_delete.map { |header| delete(header) }
  end

  self  # for chaining
end
each(&block)

In the default mixed mode or row mode, iteration is the standard row major walking of rows. In column mode, interation will yield two element tuples containing the column name and an Array of values for that column.

This method returns the table for chaining.

Source: show | on GitHub 

# File lib/csv.rb, line 841
def each(&block)
  if @mode == :col
    headers.each { |header| block[[header, self[header]]] }
  else
    @table.each(&block)
  end

  self  # for chaining
end
headers()

Returns the headers for the first row of this table (assumed to match all other rows). An empty Array is returned for empty tables.

Source: show | on GitHub 

# File lib/csv.rb, line 673
def headers
  if @table.empty?
    Array.new
  else
    @table.first.headers
  end
end
inspect()

Shows the mode and size of this table in a US-ASCII String.

Source: show | on GitHub 

# File lib/csv.rb, line 890
def inspect
  "#<#{self.class} mode:#{@mode} row_count:#{to_a.size}>".encode("US-ASCII")
end
push(*rows)

A shortcut for appending multiple rows. Equivalent to:

rows.each { |row| self << row }

This method returns the table for chaining.

Source: show | on GitHub 

# File lib/csv.rb, line 790
def push(*rows)
  rows.each { |row| self << row }

  self  # for chaining
end
to_a()

Returns the table as an Array of Arrays. Headers will be the first row, then all of the field rows will follow.

Source: show | on GitHub 

# File lib/csv.rb, line 860
def to_a
  @table.inject([headers]) do |array, row|
    if row.header_row?
      array
    else
      array + [row.fields]
    end
  end
end
to_csv(options = Hash.new)

Returns the table as a complete CSV String. Headers will be listed first, then all of the field rows.

This method assumes you want the #headers, unless you explicitly pass :write_headers => false.

Also aliased as: to_s

Source: show | on GitHub 

# File lib/csv.rb, line 877
def to_csv(options = Hash.new)
  wh = options.fetch(:write_headers, true)
  @table.inject(wh ? [headers.to_csv(options)] : [ ]) do |rows, row|
    if row.header_row?
      rows
    else
      rows + [row.fields.to_csv(options)]
    end
  end.join('')
end
to_s(options = Hash.new)
Alias for: to_csv
values_at(*indices_or_headers)

The mixed mode default is to treat a list of indices as row access, returning the rows indicated. Anything else is considered columnar access. For columnar access, the return set has an Array for each row with the values indicated by the headers in each Array. You can force column or row mode using #by_col!() or #by_row!().

You cannot mix column and row access.

Source: show | on GitHub 

# File lib/csv.rb, line 752
def values_at(*indices_or_headers)
  if @mode == :row or  # by indices
     ( @mode == :col_or_row and indices_or_headers.all? do |index|
                                  index.is_a?(Integer)         or
                                  ( index.is_a?(Range)         and
                                    index.first.is_a?(Integer) and
                                    index.last.is_a?(Integer) )
                                end )
    @table.values_at(*indices_or_headers)
  else                 # by headers
    @table.map { |row| row.values_at(*indices_or_headers) }
  end
end