1######################################################################## 2## 3## Copyright (C) 1996-2021 The Octave Project Developers 4## 5## See the file COPYRIGHT.md in the top-level directory of this 6## distribution or <https://octave.org/copyright/>. 7## 8## This file is part of Octave. 9## 10## Octave is free software: you can redistribute it and/or modify it 11## under the terms of the GNU General Public License as published by 12## the Free Software Foundation, either version 3 of the License, or 13## (at your option) any later version. 14## 15## Octave is distributed in the hope that it will be useful, but 16## WITHOUT ANY WARRANTY; without even the implied warranty of 17## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18## GNU General Public License for more details. 19## 20## You should have received a copy of the GNU General Public License 21## along with Octave; see the file COPYING. If not, see 22## <https://www.gnu.org/licenses/>. 23## 24######################################################################## 25 26## -*- texinfo -*- 27## @deftypefn {} {} index (@var{s}, @var{t}) 28## @deftypefnx {} {} index (@var{s}, @var{t}, @var{direction}) 29## Return the position of the first occurrence of the string @var{t} in the 30## string @var{s}, or 0 if no occurrence is found. 31## 32## @var{s} may also be a string array or cell array of strings. 33## 34## For example: 35## 36## @example 37## @group 38## index ("Teststring", "t") 39## @result{} 4 40## @end group 41## @end example 42## 43## If @var{direction} is @qcode{"first"}, return the first element found. 44## If @var{direction} is @qcode{"last"}, return the last element found. 45## 46## @seealso{find, rindex} 47## @end deftypefn 48 49function n = index (s, t, direction = "first") 50 51 if (nargin < 2 || nargin > 3) 52 print_usage (); 53 endif 54 55 if (ischar (s)) 56 if (! isrow (s)) 57 s = cellstr (s); # Handle string arrays by conversion to cellstr 58 endif 59 elseif (! iscellstr (s)) 60 error ("index: S must be a string, string array, or cellstr"); 61 endif 62 63 f = strfind (s, t); 64 if (isempty (f)) 65 f = 0; 66 elseif (iscell (f)) 67 f(cellfun ("isempty", f)) = {0}; 68 endif 69 70 direction = tolower (direction); 71 72 if (strcmp (direction, "first")) 73 if (iscell (f)) 74 n = cellfun ("min", f); 75 else 76 n = f(1); 77 endif 78 elseif (strcmp (direction, "last")) 79 if (iscell (f)) 80 n = cellfun ("max", f); 81 else 82 n = f(end); 83 endif 84 else 85 error ('index: DIRECTION must be either "first" or "last"'); 86 endif 87 88endfunction 89 90 91%!assert (index ("foobarbaz", "b"), 4) 92%!assert (index ("foobarbaz", "z"), 9) 93 94%!assert (index ("astringbstringcstring", "s"), 2) 95%!assert (index ("astringbstringcstring", "st"), 2) 96%!assert (index ("astringbstringcstring", "str"), 2) 97%!assert (index ("astringbstringcstring", "string"), 2) 98%!assert (index ("abc---", "abc+++"), 0) 99 100## test everything out in reverse 101%!assert (index ("astringbstringcstring", "s", "last"), 16) 102%!assert (index ("astringbstringcstring", "st", "last"), 16) 103%!assert (index ("astringbstringcstring", "str", "last"), 16) 104%!assert (index ("astringbstringcstring", "string", "last"), 16) 105%!assert (index ("abc---", "abc+++", "last"), 0) 106 107%!test 108%! str = char ("Hello", "World", "Goodbye", "World"); 109%! assert (index (str, "o"), [5; 2; 2; 2]); 110%! assert (index (str, "o", "last"), [5; 2; 3; 2]); 111%! str = cellstr (str); 112%! assert (index (str, "o"), [5; 2; 2; 2]); 113%! assert (index (str, "o", "last"), [5; 2; 3; 2]); 114 115## Test input validation 116%!error index () 117%!error index ("a") 118%!error index ("a", "b", "first", "d") 119%!error index (1, "bar") 120%!error index ("foo", "bar", 3) 121