Class: RFits::ColumnInformationList

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

Overview

A list of ColumnInformation objects representing the set of column definitions. Behaves much like an array.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table) ⇒ ColumnInformationList

Create a list of ColumnInformation from the specified table.

cil = ColumnInformationList.new(table)



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# File 'lib/rfits/rfits.rb', line 1184

def initialize(table)
  @table = table
end

Instance Attribute Details

#table ⇒ Object (readonly)

The table the columns belong to.



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# File 'lib/rfits/rfits.rb', line 1180

def table
  @table
end

Instance Method Details

#<<(options) ⇒ Object

Append a new column to the table. See ColumnInformationList#[]= for details on what “options” can look like.

cil << {:name => 'new_column_1', :format => 'A10'}
cil << [{:name => 'new_column_1', :format => 'A10'}, {:name => 'new_column_2', :format => 'I'}]



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# File 'lib/rfits/rfits.rb', line 1234

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

#[](i) ⇒ Object

Retrieve the ith column’s information.

cil[1]  # the second column's information



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# File 'lib/rfits/rfits.rb', line 1190

def [](i)
  self.table.reset_position
  ColumnInformation.new(self.table, i)
end

#[]=(i, options) ⇒ Object

Insert a column into the ith position. “options” is a hash with two keys:

:name

the name of the column

:format

the format of the column as explained in the cfitsio documentation

You can also insert multiple columns at the same time by passing an array of hashes of the format explained above.

cil[1] = {:name => 'new_column_1', :format => 'A10'}
cil[1] = [{:name => 'new_column_1', :format => 'A10'}, {:name => 'new_column_2', :format => 'I'}]



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# File 'lib/rfits/rfits.rb', line 1205

def []=(i, options)
  self.table.reset_position
  
  names = []
  formats = []
  if options.is_a?(Array)
    options.each do |spec|
      names << spec[:name]
      formats << spec[:format]
    end
  else
    names = [options[:name]]
    formats = [options[:format]]
  end
  
  IO::Proxy.fits_insert_cols(self.table.file.io, i+1, names.size, names, formats)
end

#delete(i) ⇒ Object

Delete the ith column.

cil.delete(1)  # delete the second column



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# File 'lib/rfits/rfits.rb', line 1240

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

#each ⇒ Object

Iterate through each ColumnInformation object.



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# File 'lib/rfits/rfits.rb', line 1224

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

#size ⇒ Object

The number of columns in the table.

cil.size  # 4



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# File 'lib/rfits/rfits.rb', line 1247

def size
  self.table.reset_position
  IO::Proxy.fits_get_num_cols(self.table.file.io)
end