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[CreaPhase.git] / octave_packages / m / strings / index.m

diff --git a/octave_packages/m/strings/index.m b/octave_packages/m/strings/index.m
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+## Copyright (C) 1996-2012 Kurt Hornik
+##
+## 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
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {} index (@var{s}, @var{t})
+## @deftypefnx {Function File} {} index (@var{s}, @var{t}, @var{direction})
+## Return the position of the first occurrence of the string @var{t} in the
+## string @var{s}, or 0 if no occurrence is found.  @var{s} may also be a
+## string array or cell array of strings.
+##
+## For example:
+##
+## @example
+## @group
+## index ("Teststring", "t")
+##    @result{} 4
+## @end group
+## @end example
+##
+## If @var{direction} is @samp{"first"}, return the first element found.
+## If @var{direction} is @samp{"last"}, return the last element found.
+##
+## @seealso{find, rindex}
+## @end deftypefn
+
+## Author: Kurt Hornik <Kurt.Hornik@wu-wien.ac.at>
+## Adapted-By: jwe
+## This is patterned after the AWK function of the same name.
+
+function n = index (s, t, direction = "first")
+
+  if (nargin < 2 || nargin > 3)
+    print_usage ();
+  endif
+
+  if (ischar (s))
+    if (! isrow (s))
+      s = cellstr (s);  # Handle string arrays by conversion to cellstr
+    endif
+  elseif (! iscellstr (s))
+    error ("index: S must be a string, string array, or cellstr");
+  endif
+
+  f = strfind (s, t);
+  if (isempty (f))
+    f = 0;
+  elseif (iscell (f))
+    f(cellfun ("isempty", f)) = {0};
+  endif
+
+  direction = tolower (direction);
+
+  if (strcmp (direction, "first"))
+    if (iscell (f))
+      n = cellfun ("min", f);
+    else
+      n = f(1);
+    endif
+  elseif (strcmp (direction, "last"))
+    if (iscell (f))
+      n = cellfun ("max", f);
+    else
+      n = f(end);
+    endif
+  else
+    error ('index: DIRECTION must be either "first" or "last"');
+  endif
+
+endfunction
+
+
+%!assert (index ("foobarbaz", "b") == 4 && index ("foobarbaz", "z") == 9);
+
+%!assert (index("astringbstringcstring", "s"), 2)
+%!assert (index("astringbstringcstring", "st"), 2)
+%!assert (index("astringbstringcstring", "str"), 2)
+%!assert (index("astringbstringcstring", "string"), 2)
+%!assert (index("abc---", "abc+++"), 0)
+
+## test everything out in reverse
+%!assert (index("astringbstringcstring", "s", "last"), 16)
+%!assert (index("astringbstringcstring", "st", "last"), 16)
+%!assert (index("astringbstringcstring", "str", "last"), 16)
+%!assert (index("astringbstringcstring", "string", "last"), 16)
+%!assert (index("abc---", "abc+++", "last"), 0)
+
+%!test
+%! str = char ("Hello", "World", "Goodbye", "World");
+%! assert (index (str, "o"), [5; 2; 2; 2]);
+%! assert (index (str, "o", "last"), [5; 2; 3; 2]);
+%! str = cellstr (str);
+%! assert (index (str, "o"), [5; 2; 2; 2]);
+%! assert (index (str, "o", "last"), [5; 2; 3; 2]);
+
+%% Test input validation
+%!error index ()
+%!error index ("a")
+%!error index ("a", "b", "first", "d")
+%!error index (1, "bar")
+%!error index ("foo", "bar", 3)
+