Class: RFits::TableData

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/rfits/rfits.rb

Overview

Represents tabular data in a FITS file.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table) ⇒ TableData

Create a TableData object that is associated with the specifed table.

data = TableData.new(table)



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# File 'lib/rfits/rfits.rb', line 614

def initialize(table)
  @table = table
end

Instance Attribute Details

#table ⇒ Object (readonly)

The table the data lives in.



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# File 'lib/rfits/rfits.rb', line 610

def table
  @table
end

Instance Method Details

#<<(values) ⇒ Object

Append a new row.

data << ['new', 2.2, 7, Complex.new(5, 5)]



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# File 'lib/rfits/rfits.rb', line 701

def <<(values)
  self[self.size] = values
end

#[](*args) ⇒ Object

Retrieve the ith row of data.

data[2]  # ['a1', 1.1, 3, Complex.new(3, 4)]

or the value of the cell at the specified row and column.

data[2, 3] # Complex.new(3, 4)  # the 4th cell in the 3rd row



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# File 'lib/rfits/rfits.rb', line 641

def [](*args)
  self.table.reset_position
  
  result = case args.length
    when 1 # retrieve the whole row
      row = []
      (0...self.table.column_information.size).each do |col|
        row << IO::Proxy.fits_read_col(self.table.file.io,
          self.table.column_information[col].data_type(true),
          col+1, (args.first.to_i+1), 1, 1, nil).first.first
      end
      row
    when 2 # retrieve the value of the cell
      IO::Proxy.fits_read_col(self.table.file.io,
        self.table.column_information[args.last].data_type(true),
        (args.last.to_i)+1, (args.first.to_i)+1, 1, 1, nil).first.first
    else
      raise ArgumentError, "Selector should be an integer indicating the row, or two integers indicating the row and column."
  end
  
  result
end

#[]=(*args) ⇒ Object

Set the ith row to the specified values

data[4] = ['new', 2.2, 7, Complex.new(5, 5)]

or specify the value of a particular cell

data[4, 1] = 2.2  # the second column of the 5th row



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# File 'lib/rfits/rfits.rb', line 673

def []=(*args)
  self.table.reset_position
  
  i = args.first
  
  case args.length
    when 2
      values = args[1..-1].first
      
      (0...values.size).each do |col|
        IO::Proxy.fits_write_colnull(self.table.file.io,
          self.table.column_information[col].data_type(true), col+1, i+1, 1, 1,
          [values[col]], nil)
      end
    when 3
      col = args[1]
      values = args[2..-1]
      
      IO::Proxy.fits_write_colnull(self.table.file.io,
        self.table.column_information[col].data_type(true), col+1, i+1, 1, 1,
        values, nil)
    else
      raise ArgumentError, "Selector should be an integer indicating the row, or two integers indicating the row and column."
  end
end

#column(i) ⇒ Object

Retrieve the ith column.

data.column(2)  # [1, 2, 3, 4, 5]



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# File 'lib/rfits/rfits.rb', line 630

def column(i)
  self.table.reset_position
  
  IO::Proxy.fits_read_col(self.table.file.io,
    self.table.column_information[i].data_type(true), i+1, 1, 1, self.size, nil).first
end

#delete(i) ⇒ Object

Delete the ith row.

table.delete(2)  # delete the 3rd row



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# File 'lib/rfits/rfits.rb', line 724

def delete(i)
  self.table.reset_position
  IO::Proxy.fits_delete_rows(self.table.file.io, i+1, 1)
end

#each ⇒ Object

Iterate through each row in the table.



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# File 'lib/rfits/rfits.rb', line 737

def each
  self.table.reset_position
  
  (0...self.size).each do |i|
    yield self[i]
  end
end

#each_column ⇒ Object

Iterate through each column in the table.



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# File 'lib/rfits/rfits.rb', line 746

def each_column
  (0...self.table.column_information.size).each do |i|
    yield self.column(i)
  end
end

#each_row ⇒ Object

Alias for TableData#each.



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# File 'lib/rfits/rfits.rb', line 730

def each_row
  self.each do |row|
    yield row
  end
end

#first ⇒ Object

Retrieve the first row in the table.

table.first  # ['blah', 23.1, 9, Complex.new(4, 5)]



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# File 'lib/rfits/rfits.rb', line 754

def first
  self[0]
end

#last ⇒ Object

Retrieve the last row in the table.

table.last  # ['new', 2.2, 7, Complex.new(5, 5)]



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# File 'lib/rfits/rfits.rb', line 760

def last
  self[self.size - 1]
end

#length ⇒ Object

The number of rows in the table.

table.length  # 5



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# File 'lib/rfits/rfits.rb', line 712

def length
  self.table.reset_position
  IO::Proxy.fits_get_num_rows(self.table.file.io)
end

#row(i) ⇒ Object

Alias for TableData#[]



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# File 'lib/rfits/rfits.rb', line 665

def row(i)
  self[i]
end

#set_column(i, values) ⇒ Object

Set the ith columns to the specified values.

data.set_column(2, [1, 2, 3, 4, 5])  # set the 3rd column (which is an integer column)



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# File 'lib/rfits/rfits.rb', line 620

def set_column(i, values)
  self.table.reset_position
  
  IO::Proxy.fits_write_colnull(self.table.file.io,
    self.table.column_information[i].data_type(true), i+1, 1, 1, values.size,
    values, nil)
end

#set_row(i, values) ⇒ Object

Alias for TableData#[]=



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# File 'lib/rfits/rfits.rb', line 706

def set_row(i, values)
  self[i] = values
end

#size ⇒ Object

Alias for TableData#length



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# File 'lib/rfits/rfits.rb', line 718

def size
  self.length
end

#to_csv ⇒ Object

Convert the rows in the table to CSV.



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# File 'lib/rfits/rfits.rb', line 770

def to_csv
  buffer = ''

  self.each_row do |row|
    CSV.generate_row(row.collect{ |cell| cell.to_s }, row.size, buffer)
  end
  
  buffer
end

#to_s ⇒ Object

Convert the rows to a string. Currently an alias to TableData#to_csv



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# File 'lib/rfits/rfits.rb', line 765

def to_s
  self.to_csv
end