Class: RFits::ColumnInformation

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

Overview

A class that encapsulates knowledge about the name and type of a column in a table.

Constant Summary collapse

COLUMN_TYPE_MAP = 
{
  IO::Proxy::TBIT => :bit,
  IO::Proxy::TBYTE => :byte,
  IO::Proxy::TLOGICAL => :logical,
  IO::Proxy::TSTRING => :string,
  IO::Proxy::TSHORT => :short,
  IO::Proxy::TLONG => :long,
  IO::Proxy::TFLOAT => :float,
  IO::Proxy::TDOUBLE => :double,
  IO::Proxy::TCOMPLEX => :complex,
  IO::Proxy::TDBLCOMPLEX => :dblcomplex
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table, position) ⇒ ColumnInformation

Create a new ColumnInformation object on the specified table (of type AsciiTable or BinaryTable) at the specified location (a zero-based index).

ci = ColumnInformation.new(tbl, 2)   # the third column in the table



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# File 'lib/rfits/rfits.rb', line 1094

def initialize(table, position)
  @table = table
  @position = position
end

Instance Attribute Details

#position ⇒ Object (readonly)

The position of the column in the table.



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# File 'lib/rfits/rfits.rb', line 1089

def position
  @position
end

#table ⇒ Object (readonly)

The table the column belongs to.



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# File 'lib/rfits/rfits.rb', line 1086

def table
  @table
end

Instance Method Details

#data_type(as_int = false) ⇒ Object

The data type of the column. May be one of:

:bit, :byte, :logical, :string, :short, :long, :float, :double, :complex, :dblcomplex

If the data type is unrecognized, an integer corresponding to the cfitsio data type will be returned instead.

ci.data_type   # :string



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# File 'lib/rfits/rfits.rb', line 1111

def data_type(as_int=false)
  self.table.reset_position
  type_info = IO::Proxy.fits_get_coltype(self.table.file.io, self.position+1)
  
  as_int ? type_info[0] : COLUMN_TYPE_MAP[type_info[0]] || type_info[0]
end

#dim(maxdim = 1) ⇒ Object

The number of dimensions of the column. “maxdim” is the maximum number of dimensions to return and defaults to 1.

ci.dim  # 1



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# File 'lib/rfits/rfits.rb', line 1146

def dim(maxdim=1)
  self.table.reset_position
  dim_info = IO::Proxy.fits_read_tdim(self.table.file.io, self.position+1, 1)
  
  dim_info[0]
end

#display_width ⇒ Object

The display width (i.e. the width of the column if it were to be converted into it’s string representation).

ci.display_width  # 10



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# File 'lib/rfits/rfits.rb', line 1138

def display_width
  self.table.reset_position
  IO::Proxy.fits_get_col_display_width(self.table.file.io, self.position+1)
end

#name ⇒ Object

The name of the column.

ci.name   # 'column_3'



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# File 'lib/rfits/rfits.rb', line 1101

def name
  self.table.reset_position
  IO::Proxy.fits_get_colname(self.table.file.io, IO::Proxy::CASEINSEN, "#{self.position + 1}").first
end

#naxes(*args) ⇒ Object

An alias for ColumnInformation#size



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# File 'lib/rfits/rfits.rb', line 1169

def naxes(*args)
  self.size(*args)
end

#naxis(*args) ⇒ Object

An alias for ColumnInformation#dim



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# File 'lib/rfits/rfits.rb', line 1154

def naxis(*args)
  self.dim(*args)
end

#repeat ⇒ Object

The vector repeat count of the column. An AsciiTable will always have a repeat of 1.

ci.repeat  # 10



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# File 'lib/rfits/rfits.rb', line 1120

def repeat
  self.table.reset_position
  type_info = IO::Proxy.fits_get_coltype(self.table.file.io, self.position+1)
  
  type_info[1]
end

#size(maxdim = 1) ⇒ Object

The size of the dimensions of the column. “maxdim” is the maximum number of dimensions to return and defaults to 1.

ci.size  # [1]



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# File 'lib/rfits/rfits.rb', line 1161

def size(maxdim=1)
  self.table.reset_position
  dim_info = IO::Proxy.fits_read_tdim(self.table.file.io, self.position+1, maxdim)
  
  return dim_info[1]
end

#width ⇒ Object

The width, in bytes, of the column.

ci.width  # 10



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# File 'lib/rfits/rfits.rb', line 1129

def width
  self.table.reset_position
  type_info = IO::Proxy.fits_get_coltype(self.table.file.io, self.position+1)
  
  type_info[2]
end