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########################################################################
##
## Copyright (C) 1993-2024 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{str} =} num2str (@var{x})
## @deftypefnx {} {@var{str} =} num2str (@var{x}, @var{precision})
## @deftypefnx {} {@var{str} =} num2str (@var{x}, @var{format})
## Convert a number (or array) to a string (or a character array).
##
## The optional second argument may either give the number of significant
## digits (@var{precision}) to be used in the output or a format template
## string (@var{format}) as in @code{sprintf} (@pxref{Formatted Output}).
## @code{num2str} can also process complex numbers.
##
## Examples:
##
## @example
## num2str (123.456)
## @result{} 123.456
##
## num2str (123.456, 4)
## @result{} 123.5
##
## s = num2str ([1, 1.34; 3, 3.56], "%5.1f")
## @result{} s =
## 1.0 1.3
## 3.0 3.6
## whos s
## @result{} Variables in the current scope:
## Attr Name Size Bytes Class
## ==== ==== ==== ===== =====
## s 2x8 16 char
## Total is 16 elements using 16 bytes
##
## num2str (1.234 + 27.3i)
## @result{} 1.234+27.3i
## @end example
##
## The @code{num2str} function is not very flexible. For better control
## over the results, use @code{sprintf} (@pxref{Formatted Output}).
##
## Programming Notes:
##
## For @sc{matlab} compatibility, leading spaces are stripped before returning
## the string.
##
## Integers larger than @code{flintmax} may not be displayed correctly.
##
## For complex @var{x}, the format string may only contain one output
## conversion specification and nothing else. Otherwise, results will be
## unpredictable.
##
## Any optional @var{format} specified by the programmer is used without
## modification. This is in contrast to @sc{matlab} which tampers with the
## @var{format} based on internal heuristics.
## @seealso{sprintf, int2str, mat2str}
## @end deftypefn
function str = num2str (x, arg)
if (nargin < 1)
print_usage ();
elseif (! (isnumeric (x) || islogical (x) || ischar (x)))
error ("num2str: X must be a numeric, logical, or character array");
endif
if (ischar (x))
str = x;
elseif (isempty (x))
str = "";
elseif (isreal (x))
if (nargin == 2)
if (ischar (arg))
fmt = arg;
elseif (isnumeric (arg) && isscalar (arg) && arg >= 0 && arg == fix (arg))
if (isfloat (x))
fmt = sprintf ("%%%d.%dg", arg+7, arg);
else
fmt = sprintf ("%%%dd", arg);
endif
else
error ("num2str: PRECISION must be a scalar integer >= 0");
endif
else
if (isnumeric (x))
## Set up a suitable format string while ignoring Inf/NaN entries
valid = isfinite (x(:));
ndgt = floor (log10 (max (abs (x(valid)))));
if (isempty (ndgt) || ndgt == -Inf)
ndgt = 0; # All Inf or all zero array
endif
if (ndgt > 15 || any (x(valid) != fix (x(valid))))
## Floating point input
ndgt = max (ndgt + 5, 5); # Keep at least 5 significant digits
ndgt = min (ndgt, 16); # Cap significant digits at 16
fmt = sprintf ("%%%d.%dg", ndgt+7, ndgt);
else
## Integer input
ndgt += 3;
if (any (! valid))
ndgt = max (ndgt, 5); # Allow space for Inf/NaN
endif
if (isfloat (x))
fmt = sprintf ("%%%d.0f", ndgt);
else
fmt = sprintf ("%%%dd", ndgt);
endif
endif
else
## Logical input
fmt = "%3d";
endif
endif
fmt = do_string_escapes (fmt); # required now that '\n' is interpreted.
nd = ndims (x);
nc = columns (x) * (nd - 1); # ND-arrays are expanded in columns
x = permute (x, [2, 3:nd, 1]);
if (! (sum (strrep (fmt, "%%", "") == "%") > 1
|| any (strcmp (fmt, {"%s", "%c"}))))
fmt = [deblank(repmat (fmt, 1, nc)), "\n"];
endif
strtmp = sprintf (fmt, x);
str = strtrim (char (ostrsplit (strtmp, "\n", true)));
else # Complex matrix input
if (nargin == 2)
if (ischar (arg))
fmt = [deblank(arg) "%-+" arg(2:end) "i"];
elseif (isnumeric (arg) && isscalar (arg) && arg >= 0 && arg == fix (arg))
fmt = sprintf ("%%%d.%dg%%-+%d.%dgi", arg+7, arg, arg+7, arg);
else
error ("num2str: PRECISION must be a scalar integer >= 0");
endif
else
## Set up a suitable format string while ignoring Inf/NaN entries
valid_real = isfinite (real (x(:)));
valid_imag = isfinite (imag (x(:)));
ndgt = floor (log10 (max (max (abs (real (x(valid_real)))),
max (abs (imag (x(valid_imag)))))));
if (isempty (ndgt) || ndgt == -Inf)
ndgt = 0; # All Inf or all zero array
endif
if (any (x(valid_real & valid_imag) != fix (x(valid_real & valid_imag))))
## Floating point input
ndgt = max (ndgt + 5, 5); # Keep at least 5 significant digits
ndgt = min (ndgt, 16); # Cap significant digits at 16
fmt = sprintf ("%%%d.%dg%%-+%d.%dgi", ndgt+7, ndgt, ndgt+7, ndgt);
else
## Integer input
ndgt += 3;
## FIXME: Integers must be masked to show only 16 significant digits
## See test case for bug #36133 below
fmt = sprintf ("%%%d.0f%%-+%d.0fi", ndgt, ndgt);
endif
endif
## Manipulate the complex value to have real values in the odd
## columns and imaginary values in the even columns.
nd = ndims (x);
nc = columns (x);
idx = repmat ({':'}, nd, 1);
perm(1:2:2*nc) = 1:nc;
perm(2:2:2*nc) = nc + (1:nc);
idx{2} = perm;
x = horzcat (real (x), imag (x));
x = x(idx{:});
fmt = [deblank(repmat(fmt, 1, nc * (nd - 1))), "\n"];
tmp = sprintf (fmt, permute (x, [2, 3:nd, 1]));
## Put the "i"'s where they are supposed to be.
tmp = regexprep (tmp, " +i\n", "i\n");
tmp = regexprep (tmp, "( +)i", "i$1");
str = strtrim (char (ostrsplit (tmp(1:end-1), "\n")));
endif
endfunction
## Basic tests
%!assert (num2str (123), "123")
%!assert (num2str (1.23), "1.23")
%!assert (num2str (123.456, 4), "123.5")
%!assert (num2str ([1, 1.34; 3, 3.56], "%5.1f"), ["1.0 1.3"; "3.0 3.6"])
%!assert (num2str (1.234 + 27.3i), "1.234+27.3i")
%!assert (num2str ([true false true]), "1 0 1")
## Exceptional values
%!assert (num2str (19440606), "19440606")
%!assert (num2str (2^33), "8589934592")
%!assert (num2str (-2^33), "-8589934592")
%!assert (num2str (2^33+1i), "8589934592+1i")
%!assert (num2str (-2^33+1i), "-8589934592+1i")
%!assert (num2str ([0 0 0]), "0 0 0")
%!assert (num2str (inf), "Inf")
%!assert (num2str ([inf -inf]), "Inf -Inf")
%!assert (num2str ([inf NaN -inf]), "Inf NaN -Inf")
%!assert (num2str ([complex(Inf,0), complex(0,-Inf)]), "Inf+0i 0-Infi")
%!assert (num2str (complex (Inf,1)), "Inf+1i")
%!assert (num2str (complex (1,Inf)), "1+Infi")
%!assert (num2str (nan), "NaN")
%!assert (num2str (complex (NaN, 1)), "NaN+1i")
%!assert (num2str (complex (1, NaN)), "1+NaNi")
%!assert (num2str (NA), "NA")
%!assert (num2str (complex (NA, 1)), "NA+1i")
%!assert (num2str (complex (1, NA)), "1+NAi")
%!assert (num2str (int64 (-flintmax ()) - 1), "-9007199254740993")
%!assert (num2str (int64 (-flintmax ()) - 1, 18), "-9007199254740993")
## ND-arrays are concatenated in columns
%!shared m, x
%! m = magic (3);
%! x = cat (3, m, -m);
## real case
%!test <*46770>
%! y = num2str (x);
%! assert (rows (y) == 3);
%! assert (y, ["8 1 6 -8 -1 -6"
%! "3 5 7 -3 -5 -7"
%! "4 9 2 -4 -9 -2"]);
## complex case
%!test <*46770>
%! x(1,1,2) = -8+2i;
%! y = num2str (x);
%! assert (rows (y) == 3);
%! assert (y, ["8+0i 1+0i 6+0i -8+2i -1+0i -6+0i"
%! "3+0i 5+0i 7+0i -3+0i -5+0i -7+0i"
%! "4+0i 9+0i 2+0i -4+0i -9+0i -2+0i"]);
## Clear shared variables
%!shared
## Integers greater than 1e15 should switch to exponential notation
%!assert <*36133> (num2str (1e15), "1000000000000000")
%!assert <*36133> (num2str (1e16), "1e+16")
## Even exact integers in IEEE notation should use exponential notation
%!assert <*36133> (num2str (2^512), "1.34078079299426e+154")
## Mixed integer/floating point arrays
%!assert <*36133> (num2str ([2.1, 1e23, pi]),
%! "2.1 9.999999999999999e+22 3.141592653589793")
## Large integers should not switch sign when printed due to overflow
%!assert <*36121> (num2str (2.4e9, 15), "2400000000")
## Test for extra rows generated from newlines in format
%!assert <*44864> (rows (num2str (magic (3), "%3d %3d %3d\n")), 3)
## Test that string conversion of numeric objects results in characters
## if the numbers are within range for ASCII.
%!assert <*45174> (num2str ([65 66 67], "%s"), "ABC")
## Test input validation
%!error <Invalid call> num2str ()
%!error <X must be a numeric> num2str ({1})
%!error <PRECISION must be a scalar integer .= 0> num2str (1, {1})
%!error <PRECISION must be a scalar integer .= 0> num2str (1, ones (2))
%!error <PRECISION must be a scalar integer .= 0> num2str (1, -1)
%!error <PRECISION must be a scalar integer .= 0> num2str (1, 1.5)
%!error <PRECISION must be a scalar integer .= 0> num2str (1+1i, {1})
%!error <PRECISION must be a scalar integer .= 0> num2str (1+1i, ones (2))
%!error <PRECISION must be a scalar integer .= 0> num2str (1+1i, -1)
%!error <PRECISION must be a scalar integer .= 0> num2str (1+1i, 1.5)
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