Mercurial > octave
view scripts/strings/substr.m @ 31239:dd6b37f67db2
Accept negative inputs to -2^63 for dec2bin and dec2hex (bug #63089)
dec2bin.m: Accept negative inputs lower than -flintmax down to -2^63
Return 64-bit string in certain cases for Matlab compatibility
Activate BISTs commented out earlier
dec2hex.m: Remove repeated code and call dec2bin instead
Accept negative inputs lower than -flintmax down to -2^63
Update and activate BISTs commented out earlier
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Sun, 25 Sep 2022 06:22:25 -0400 |
parents | 5d3faba0342e |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 1996-2022 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{str} =} substr (@var{s}, @var{offset}) ## @deftypefnx {} {} substr (@var{s}, @var{offset}, @var{len}) ## Return the substring of @var{s} which starts at character number ## @var{offset} and is @var{len} characters long. ## ## Position numbering for offsets begins with 1. If @var{offset} is negative, ## extraction starts that far from the end of the string. ## ## If @var{len} is omitted, the substring extends to the end of @var{s}. A ## negative value for @var{len} extracts to within @var{len} characters of ## the end of the string ## ## Examples: ## ## @example ## @group ## substr ("This is a test string", 6, 9) ## @result{} "is a test" ## substr ("This is a test string", -11) ## @result{} "test string" ## substr ("This is a test string", -11, -7) ## @result{} "test" ## @end group ## @end example ## ## This function is patterned after the equivalent function in Perl. ## @end deftypefn function str = substr (s, offset, len) if (nargin < 2) print_usage (); endif if (! ischar (s)) error ("substr: S must be a string or string array"); elseif (! isscalar (offset) || (nargin == 3 && ! isscalar (len))) error ("substr: OFFSET and LEN must be scalar integers"); endif offset = fix (offset); nc = columns (s); if (abs (offset) > nc || offset == 0) error ("substr: OFFSET = %d out of range", offset); endif if (offset <= 0) offset += nc + 1; endif if (nargin == 2) eos = nc; else len = fix (len); if (len < 0) eos = nc + len; else eos = offset + len - 1; endif endif if (eos > nc) error ("substr: length LEN = %d out of range", len); elseif (offset > eos && len != 0) error ("substr: No overlap with chosen values of OFFSET and LEN"); endif str = s(:, offset:eos); endfunction %!assert (substr ("This is a test string", 6, 9), "is a test") %!assert (substr ("This is a test string", -11), "test string") %!assert (substr ("This is a test string", -11, 4), "test") %!assert (substr ("This is a test string", -11, -7), "test") %!assert (substr ("This is a test string", 1, -7), "This is a test") %!assert (isempty (substr ("This is a test string", 1, 0))) ## Test input validation %!error <Invalid call> substr () %!error substr ("foo", 2, 3, 4) %!error substr (ones (5, 1), 1, 1) %!error substr ("foo", ones (2,2)) %!error substr ("foo", 1, ones (2,2)) %!error substr ("foo", 0) %!error substr ("foo", 5) %!error substr ("foo", 1, 5) %!error substr ("foo", -1, 5) %!error substr ("foo", 2, -5)