## Mercurial > hg > octave-max

### view scripts/strings/findstr.m @ 15489:481417a57a2d

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improve sign and signbit docs
* mappers.cc (Fsign): Note sign (-0) is 0. Add @seealso for signbit.
(Fsignbit): Add @seealso for sign.

author | John W. Eaton <jwe@octave.org> |
---|---|

date | Thu, 04 Oct 2012 10:20:59 -0400 |

parents | f3d52523cde1 |

children |

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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} {} findstr (@var{s}, @var{t}) ## @deftypefnx {Function File} {} findstr (@var{s}, @var{t}, @var{overlap}) ## Return the vector of all positions in the longer of the two strings ## @var{s} and @var{t} where an occurrence of the shorter of the two starts. ## If the optional argument @var{overlap} is true, the returned vector ## can include overlapping positions (this is the default). For example: ## ## @example ## @group ## findstr ("ababab", "a") ## @result{} [1, 3, 5]; ## findstr ("abababa", "aba", 0) ## @result{} [1, 5] ## @end group ## @end example ## ## @strong{Caution:} @code{findstr} is scheduled for deprecation. Use ## @code{strfind} in all new code. ## @seealso{strfind, strmatch, strcmp, strncmp, strcmpi, strncmpi, find} ## @end deftypefn ## Note that this implementation swaps the strings if second one is longer ## than the first, so try to put the longer one first. ## ## Author: Kurt Hornik <Kurt.Hornik@wu-wien.ac.at> ## Adapted-By: jwe function v = findstr (s, t, overlap = true) if (nargin < 2 || nargin > 3) print_usage (); endif if (all (size (s) > 1) || all (size (t) > 1)) error ("findstr: arguments must have only one non-singleton dimension"); endif ## Make S be the longer string. if (length (s) < length (t)) [s, t] = deal (t, s); endif l_s = length (s); l_t = length (t); if (l_t == 0) ## zero length target: return empty set v = []; elseif (l_t == 1) ## length one target: simple find v = find (s == t); elseif (l_t == 2) ## length two target: find first at i and second at i+1 v = find (s(1:l_s-1) == t(1) & s(2:l_s) == t(2)); else ## length three or more: match the first three by find then go through ## the much smaller list to determine which of them are real matches limit = l_s - l_t + 1; v = find (s(1:limit) == t(1) & s(2:limit+1) == t(2) & s (3:limit+2) == t(3)); endif ## Need to search the index vector if our find was too short ## (target length > 3), or if we don't allow overlaps. Note though ## that there cannot be any overlaps if the first character in the ## target is different from the remaining characters in the target, ## so a single character, two different characters, or first character ## different from the second two don't need to be searched. if (l_t >= 3 || (! overlap && l_t > 1 && any (t(1) == t(2:l_t)))) ## force strings to be both row vectors or both column vectors if (all (size (s) != size (t))) t = t.'; endif ## determine which ones to keep keep = zeros (size (v)); ind = 0:l_t-1; if (overlap) for idx = 1:length (v) keep(idx) = all (s(v(idx) + ind) == t); endfor else ## First possible position for next non-overlapping match. next = 1; for idx = 1:length (v) if (v(idx) >= next && s(v(idx) + ind) == t) keep(idx) = 1; ## Skip to the next possible match position. next = v(idx) + l_t; else keep(idx) = 0; endif endfor endif if (! isempty (v)) v = v(find (keep)); endif endif if (isempty (v)) v = []; endif ## Always return a row vector, because that's what the old one did. if (iscolumn (v)) v = v.'; endif endfunction %!assert (findstr ("abababa", "a"), [1, 3, 5, 7]) %!assert (findstr ("abababa", "aba"), [1, 3, 5]) %!assert (findstr ("aba", "abababa", 0), [1, 5]) %% Test input validation %!error findstr () %!error findstr ("foo", "bar", 3, 4) %!error <must have only one non-singleton dimension> findstr (["AB" ; "CD"], "C")