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########################################################################
##
## Copyright (C) 1994-2024 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave 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.
##
## Octave 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 Octave; see the file COPYING. If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################
## -*- texinfo -*-
## @deftypefn {} {@var{B} =} postpad (@var{A}, @var{l})
## @deftypefnx {} {@var{B} =} postpad (@var{A}, @var{l}, @var{c})
## @deftypefnx {} {@var{B} =} postpad (@var{A}, @var{l}, @var{c}, @var{dim})
## Append the scalar value @var{c} to the vector @var{A} until it is of length
## @var{l}. If @var{c} is not given, a value of 0 is used.
##
## If @code{length (@var{A}) > @var{l}}, elements from the end of @var{A} are
## removed until a vector of length @var{l} is obtained.
##
## If @var{A} is a matrix, elements are appended or removed from each row.
##
## If the optional argument @var{dim} is given, operate along this dimension.
##
## If @var{dim} is larger than the dimensions of @var{A}, the result will have
## @var{dim} dimensions.
## @seealso{prepad, cat, resize}
## @end deftypefn
function B = postpad (A, l, c, dim)
if (nargin < 2)
print_usage ();
endif
if (nargin < 3 || isempty (c))
c = 0;
else
if (! isscalar (c))
error ("postpad: third argument must be empty or a scalar");
endif
endif
nd = ndims (A);
sz = size (A);
if (nargin < 4)
## Find the first non-singleton dimension.
(dim = find (sz > 1, 1)) || (dim = 1);
else
if (!(isscalar (dim) && dim == fix (dim) && dim >= 1))
error ("postpad: DIM must be an integer and a valid dimension");
endif
endif
if (! isscalar (l) || l < 0)
error ("postpad: second argument must be a positive scaler");
endif
if (dim > nd)
sz(nd+1:dim) = 1;
endif
d = sz(dim);
if (d == l)
## This optimization makes sense because the function is used to match
## the length between two vectors not knowing a priori is larger, and
## allow for:
## ml = max (numel (v1), numel (v2));
## v1 = postpad (v1, ml);
## v2 = postpad (v2, ml);
B = A;
elseif (d >= l)
idx = repmat ({':'}, nd, 1);
idx{dim} = 1:l;
B = A(idx{:});
else
sz(dim) = l - d;
B = cat (dim, A, c(ones (sz)));
endif
endfunction
%!assert (postpad ([1,2], 4), [1,2,0,0])
%!assert (postpad ([1;2], 4), [1;2;0;0])
%!assert (postpad ([1,2], 4, 2), [1,2,2,2])
%!assert (postpad ([1;2], 4, 2), [1;2;2;2])
%!assert (postpad ([1,2], 2, 2, 1), [1,2;2,2])
%!assert (postpad ([1;2], 2, 2, 3), reshape ([1;2;2;2], 2, 1, 2))
%!assert (postpad ([1,2], 2, 2, 3), reshape ([1,2,2,2], 1, 2, 2))
%!assert (postpad ([1 2], 2), [1 2])
%!assert (postpad ([1; 2], 2), [1; 2])
%!assert (postpad ([1; 2], 2, 3, 2), [1 3; 2 3])
%! ## Test with string concatenation
%!assert <*44162> (postpad ("Octave", 16, "x"), "Octavexxxxxxxxxx")
%!assert (postpad ("Octave", 4), "Octa")
%!error <Invalid call> postpad ()
%!error <Invalid call> postpad (1)
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