Mercurial > octave
view scripts/strings/base2dec.m @ 31246:43a6be589387
doc: New documentation for memoization techniques (bug #60860)
vectorize.texi: New section on memoization
octave.texi: List new section
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Thu, 29 Sep 2022 20:31:52 -0400 |
parents | 5d3faba0342e |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2000-2022 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{d} =} base2dec (@var{str}, @var{base}) ## Convert @var{str} from a string of digits in base @var{base} to a decimal ## integer (base 10). ## ## @example ## @group ## base2dec ("11120", 3) ## @result{} 123 ## @end group ## @end example ## ## If @var{str} is a string matrix, return a column vector with one value per ## row of @var{str}. If a row contains invalid symbols then the corresponding ## value will be NaN@. ## ## If @var{str} is a cell array of strings, return a column vector with one ## value per cell element in @var{str}. ## ## If @var{base} is a string, the characters of @var{base} are used as the ## symbols for the digits of @var{str}. Space (' ') may not be used as a ## symbol. ## ## @example ## @group ## base2dec ("yyyzx", "xyz") ## @result{} 123 ## @end group ## @end example ## @seealso{dec2base, bin2dec, hex2dec} ## @end deftypefn function d = base2dec (str, base) if (nargin != 2) print_usage (); endif if (iscellstr (str)) str = char (str); elseif (! ischar (str)) error ("base2dec: STR must be a string or cellstring"); endif symbols = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; if (ischar (base)) symbols = base; base = length (symbols); if (length (unique (symbols)) != base) error ("base2dec: symbols representing digits must be unique"); endif if (any (isspace (symbols))) error ("base2dec: whitespace characters are not valid symbols"); endif elseif (! isscalar (base)) error ("base2dec: cannot convert from several bases at once"); elseif (! (base >= 2 && base <= length (symbols))) error ("base2dec: BASE must be between 2 and 36, or a string of symbols"); else str = toupper (str); endif ## Right justify the values and squeeze out any spaces. ## This looks complicated, but indexing solution is very fast ## compared to alternatives which use cellstr or cellfun or looping. [nr, nc] = size (str); if (nc > 1) # Bug #35621 str = str.'; nonbl = str != " "; num_nonbl = sum (nonbl); nc = max (num_nonbl); num_blank = nc - num_nonbl; R = repmat ([1 2; 0 0], 1, nr); R(2, 1:2:2*nr) = num_blank; R(2, 2:2:2*nr) = num_nonbl; idx = repelems ([false, true], R); idx = reshape (idx, nc, nr); ## Create a blank matrix and position the nonblank characters. s2 = repmat (" ", nc, nr); s2(idx) = str(nonbl); str = s2.'; endif ## Lookup value of symbols in symbol table, with invalid symbols ## evaluating to NaN and space evaluating to 0. table = NaN (1, 256); table(double (symbols(1:base))) = 0 : base-1; table(double (" ")) = 0; str = reshape (table(double (str)), size (str)); ## Multiply the resulting digits by the appropriate power ## and sum the rows. d = str * (base .^ (columns (str)-1 : -1 : 0)'); endfunction %!assert (base2dec ("11120", 3), 123) %!assert (base2dec ("yyyzx", "xyz"), 123) %!assert (base2dec ("-1", 2), NaN) %!assert (base2dec ({"A1", "1A"}, 16), [161; 26]) %!assert <*35621> (base2dec (["0"; "1"], 2), [0; 1]) ## Test input validation %!error <Invalid call> base2dec () %!error base2dec ("11120") %!error base2dec ("11120", 3, 4) %!error <symbols .* must be unique> base2dec ("11120", "1231") %!error <whitespace characters are not valid> base2dec ("11120", "12 3") %!error <cannot convert from several bases> base2dec ("11120", ones (2)) %!error <BASE must be between 2 and 36> base2dec ("11120", 1) %!error <BASE must be between 2 and 36> base2dec ("11120", 37) %!error <BASE must be between 2 and 36> base2dec ("11120", NaN)