removedatafield.m.svn-base

a function inside machine learning

function d = removeDataField(d, name) 
%Remove a field from a d struct 

% Copyright (C) 2006 Charanpal Dhanjal 

% This library is free software; you can redistribute it and/or
% modify it under the terms of the GNU Lesser General Public
% License as published by the Free Software Foundation; either
% version 2.1 of the License, or (at your option) any later version.
% 
% This library is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
% Lesser General Public License for more details.
% 
% You should have received a copy of the GNU Lesser General Public
% License along with this library; if not, write to the Free Software
% Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
% USA

if (nargin ~= 2)
    fprintf('%s\n', help(sprintf('%s', mfilename)));
    error('Incorrect number of inputs - see above usage instructions.');
end

if isfield(d, 'exampleIndices') & ~isfield(d.exampleIndices, name)
    error('Field %s does not exist', name);
end

%First, decrement the reference counter
global dataValuesRefCount; 
dataValuesRefCount(d.globalIndices.(name), 1) = dataValuesRefCount(d.globalIndices.(name), 1) - 1;

%If a variable has no references - clear it!
%Note this doesn't always clear the global variables correctly if you lose
%references
%e.g. 
%d = data; d2 = data; 
%d = addDataField('X', X, 'examples'); 
%d2 = copyDataField(d, d2, 'X'); 
%d2 = data; 
%d = removeDataField(d, 'X');  -- DOES NOT REMOVE X 

if dataValuesRefCount(d.globalIndices.(name), 1) == 0
    global dataValues; 
    global dataValuesSlots; 
    
    dataValues{d.globalIndices.(name), 1} = [];
    dataValuesSlots(d.globalIndices.(name)) = 0; 
end

d.globalIndices = rmfield(d.globalIndices , name);
d.exampleIndices = rmfield(d.exampleIndices , name);
d.colIndices = rmfield(d.colIndices , name);
d.types = rmfield(d.types , name);

%If its the only field left reset numExamples
if size(getDataFieldNames(d), 1) == 0
    d.numExamples = 0;
end