## Copyright (C) 1995, 1996 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 2, 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, write to the Free ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA ## 02111-1307, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} strrep (@var{s}, @var{x}, @var{y}) ## Replaces all occurrences of the substring @var{x} of the string @var{s} ## with the string @var{y}. For example, ## ## @example ## strrep ("This is a test string", "is", "&%$") ## @result{} "Th&%$ &%$ a test string" ## @end example ## @end deftypefn ## Author: Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at> ## Created: 11 November 1994 ## Adapted-By: jwe ## Paul Kienzle <pkienzle@kienzle.powernet.co.uk> ## vectorized for speed function t = strrep (s, x, y) if (nargin <> 3) usage ("strrep (s, x, y)"); endif if (! (isstr (s) && isstr (x) && isstr (y))) error ("strrep: all arguments must be strings"); endif if (length (x) > length (s) || isempty (x)) t = s; return; endif ind = findstr (s, x, 0); if (length(ind) == 0) t = s; elseif (length(y) > 0) # replacement ## Copy the parts of s that aren't being replaced. This is done ## with an index vector, with jumps where each search string ## is found. For a jump of 0 (target length == replacement length) ## the index is just cumsum ( ones (length (s))). For non-zero ## jumps, add the jump size to the ones vector at each found position. jump = length(y) - length(x); if (jump > 0) # s expands di = ones(size(s)); di (ind) = 1 + jump * ones (length (ind), 1); t (cumsum (di)) = s; ## the following test is not needed in the octave 2.1 series if (size(s,1) == 1 && size(t,1) != 1) t = t'; endif elseif (jump < 0) # s contracts di = ones (jump * length (ind) + length (s), 1); di (ind + jump * [0:length(ind)-1]) = 1 - jump * ones(length(ind), 1); t = s (cumsum (di)); else # s stays the same length t = s; endif ## Now, substitute a copy of the replacement string whereever the ## search string was found. Note that we must first update the ## target positions to account for any expansion or contraction ## of s that may have occurred. ind = ind + jump * [ 0 : length(ind) - 1 ]; repeat = [1 : length(y)]' * ones (1, length (ind)); dest = ones (length (y), 1) * ind + repeat - 1; t (dest) = y (repeat); else # deletion ## Build an index vector of all locations where the target was found ## in the search string, and zap them. t = toascii(s); repeat = ' * ones (1, length (ind)); delete = ones (length (x), 1) * ind + repeat - 1; t (delete) = []; t = setstr(t); endif endfunction

Generated by Doxygen 1.6.0 Back to index