ft_write_tsv.m

function ft_write_tsv(filename, tsv)

% FT_WRITE_TSV writes a MATLAB table to a tab-separated-values file. Compared to the
% builtin MATLAB function, this implementation deals a bit different with missing
% values, booleans, and NaNs.
%
% Use as
%   ft_write_tsv(filename, table)
%
% See also FT_READ_TSV, FT_READ_JSON, FT_WRITE_JSON, READTABLE, WRITETABLE, TBLWRITE

% Copyright (C) 2018-2024, Robert Oostenveld
%
% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip 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 General Public License for more details.
%
%    You should have received a copy of the GNU General Public License
%    along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id$

ft_info('writing ''%s''\n', filename);
fn = tsv.Properties.VariableNames;
for i=1:numel(fn)
  % write [] as 'n/a'
  % write nan as 'n/a'
  % write boolean as 'True' or 'False'
  tsv.(fn{i}) = output_compatible(tsv.(fn{i}));
end
writetable(tsv, filename, 'Delimiter', 'tab', 'FileType', 'text');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% SUBFUNCTION this is shared with DATA2BIDS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function val = output_compatible(val)
if istable(val)
  fn = val.Properties.VariableNames;
  for i=1:numel(fn)
    val.(fn{i}) = output_compatible(val.(fn{i}));
  end
elseif iscell(val)
  % use recursion to make all elements compatible
  val = cellfun(@output_compatible, val, 'UniformOutput', false);
elseif isnumeric(val) && numel(val)>1 && any(isnan(val))
  % convert and use recursion to make all elements compatible
  val = num2cell(val);
  val = cellfun(@output_compatible, val, 'UniformOutput', false);
elseif isdatetime(val)
  val = datestr(val, 'yyyy-mm-ddTHH:MM:SS.FFF'); % following RFC3339 and BIDS 
else
  % write [] as 'n/a'
  % write nan as 'n/a'
  % write boolean as 'true' or 'talse'
  if isempty(val)
    val = 'n/a';
  elseif isnan(val)
    val = 'n/a';
  elseif islogical(val)
    if val
      val = 'true';
    else
      val = 'false';
    end
  end
end