Mercurial > jwe > octave
view scripts/miscellaneous/symvar.m @ 31170:06c76eca5f95 default tip @
maint: merge stable to default
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Fri, 29 Jul 2022 12:02:42 -0400 |
parents | 796f54d4ddbf |
children |
line wrap: on
line source
######################################################################## ## ## Copyright (C) 2008-2022 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{vars} =} symvar (@var{str}) ## Identify the symbolic variable names in the string @var{str}. ## ## Common constant names such as @code{i}, @code{j}, @code{pi}, @code{Inf} and ## Octave functions such as @code{sin} or @code{plot} are ignored. ## ## Any names identified are returned in a cell array of strings. The array is ## empty if no variables were found. ## ## Example: ## ## @example ## @group ## symvar ("x^2 + y^2 == 4") ## @result{} @{ ## [1,1] = x ## [2,1] = y ## @} ## @end group ## @end example ## @end deftypefn function vars = symvar (str) warning ("off", "Octave:legacy-function", "local"); # using inline below. vars = argnames (inline (str)); ## Correct for auto-generated 'x' variable when no symvar was found. if (numel (vars) == 1 && strcmp (vars{1}, "x") && ! any (str == "x")) vars = {}; endif endfunction %!assert (symvar ("3*x + 4*y + 5*cos (z)"), {"x"; "y"; "z"}) %!assert (symvar ("sin ()^2 + cos ()^2 == 1"), {}) %!assert (symvar ("1./x"), {"x"})