On Mon, Oct 19, 2009 at 10:00 AM, Søren Hauberg <so...@hauberg.org> wrote:
> søn, 18 10 2009 kl. 14:19 +0200, skrev Søren Hauberg:
>> I'm attaching the code for comments. It should be noted that Matlab has
>> a 'strread' function that does the same thing as 'textread' except it
>> works in strings instead of files. So, I changed the code to behave like
>> 'strread' and created a simple wrapper around this for 'textread'.
>>
>> Should I replace the current version with this one?
>
> Attached is a slightly smarter approach.
>
> Søren
>
Attached is a version that gets rid even of the last loop...
however, due to a bug in cellslices, it requires the following patch
to work correctly:
http://hg.savannah.gnu.org/hgweb/octave/rev/78ac37d73557
It's up to you whether this is OK to be included, then...
regards
--
RNDr. Jaroslav Hajek
computing expert & GNU Octave developer
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz
## Copyright (C) 2009 Eric Chassande-Mottin, CNRS (France)
##
## This program 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.
##
## This program 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 this program; if not, see
## <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {...@var{a} @var{b} ...]=}strread(@var{str},@var{format})
## @deftypefnx {Function File} {...@var{a} @var{b} ...] =}strread(@var{str},@var{format},@var{prop},@var{value})
## Read data from a dtring.
## The string @var{format} describes the different columns of @var{str} and
## It may continue the following specifiers:
## @table @code
## @item %s
## for a string,
##
## @item %d,%f
## for a double, floating-point or integer number and
##
## @item %*
## to ignore a column.
## @end table
##
## For example, the string
##
## @example
## @group
## @var{str} = "\
## Bunny Bugs 5.5\n\
## Duck Daffy -7.5e-5\n\
## Penguin Tux 6"
## @end group
## @end example
##
## can be read using
##
## @example
## @code{[a,b,c] = strread(@var{str}, "%s %s %f").}
## @end example
##
## Currently implemented @var{prop} arguments are:
## @itemize
## @item "headerlines":
## @var{value} represents the number of header lines to skip.
## @item "commentstyle":
## @var{value} is the style and can be
## @itemize
## @item "shell": comment specifier is #
## @item "c": comment specifier is /*
## @item "c++": comment specifier is //
## @item "matlab": comment specifier is %
## @end itemize
## @end itemize
##
## @seealso{textread, load, dlmread, fscanf}
## @end deftypefn
function varargout = strread (str, formatstr = "%f", varargin)
## Check input
if (nargin < 1)
print_usage ();
endif
if (!ischar (str) || !ischar (str))
error ("strread: first and second input arguments must be strings");
endif
## Parse options
comment_flag = false;
header_skip = 0;
numeric_fill_value = 0; # XXX: the user cannot set this
white_spaces = " \n\r\t"; # XXX: should the user be able to set these?
for n = 1:2:length (varargin)
switch (varargin {n})
case "commentstyle"
comment_flag = true;
switch (varargin {n+1})
case "c"
comment_specif = {"/*", "*/"};
case "c++"
comment_specif = {"//", "\n"};
case "shell"
comment_specif = {"#", "\n"};
case "matlab"
comment_specif = {"%", "\n"};
otherwise
warning ("strread: unknown comment style '%s'", val);
endswitch
case "headerlines"
header_skip = varargin {n+1};
otherwise
warning ("strread: unknown option '%s'", varargin {n});
endswitch
endfor
## Parse format string
idx = strfind (formatstr, "%")';
specif = formatstr ([idx, idx+1]);
nspecif = length (idx);
idx_star = strfind (formatstr, "%*");
nfields = length (idx) - length (idx_star);
if (nargout != nfields)
error ("strread: the number of output variables must match that of format specifiers");
endif
## Remove header
if (header_skip > 0)
e = find (str == "\n", header_skip);
if (length (e) >= header_skip)
str = str (e (end)+1:end);
else
## We don't have enough data so we discard it all
str = "";
endif
endif
## Remove comments (XXX: can this be done in a smarter way?)
if (comment_flag)
cstart = strfind (str, comment_specif{1});
cstop = strfind (str, comment_specif{2});
if (length (cstart) > 0)
## Ignore nested openers.
[idx, cidx] = unique (lookup (cstop, cstart), "first");
if (idx(end) == length (cstop))
cidx(end) = []; ## Drop the last one if orphaned.
endif
cstart = cstart(cidx);
endif
if (length (cstop) > 0)
## Ignore nested closers.
[idx, cidx] = unique (lookup (cstart, cstop), "first");
if (idx(1) == 0)
cidx(1) = []; ## Drop the first one if orphaned.
endif
cstop = cstop(cidx);
endif
len = length (str);
c2len = length (comment_specif{2});
str = cellslices (str, [1, cstop + c2len], [cstart - 1, len]);
str = [str{:}];
endif
## Split 'str' into words
words = split_by (str, white_spaces);
num_words = numel (words);
num_lines = ceil (num_words / nspecif);
## For each specifier
k = 1;
for m = 1:nspecif
data = words (m:nspecif:end);
## Map to format
switch specif (m, :)
case "%s"
data (end+1:num_lines) = {""};
varargout {k} = data';
k++;
case {"%d", "%f"}
data = str2double (data);
data (end+1:num_lines) = numeric_fill_value;
varargout {k} = data.';
k++;
case "%*"
## do nothing
endswitch
endfor
endfunction
function out = split_by (text, sep)
out = strtrim (strsplit (text, sep, true));
endfunction
%!test
%! str = "# comment\n# comment\n1 2 3";
%! [a, b] = strread (str, '%d %s', 'commentstyle', 'shell');
%! assert (a, [1; 3]);
%! assert (b, {"2"; ""});
%!test
%! str = '';
%! a = rand (10, 1);
%! b = char (round (65 + 20 * rand (10, 1)));
%! for k = 1:10
%! str = sprintf ('%s %.6f %s\n', str, a (k), b (k));
%! endfor
%! [aa, bb] = strread (str, '%f %s');
%! assert (a, aa, 1e-5);
%! assert (cellstr (b), bb);
%!test
%! str = '';
%! a = rand (10, 1);
%! b = char (round (65 + 20 * rand (10, 1)));
%! for k = 1:10
%! str = sprintf ('%s %.6f %s\n', str, a (k), b (k));
%! endfor
%! aa = strread (str, '%f %*s');
%! assert (a, aa, 1e-5);
%!test
%! str = sprintf ('/* this is\nacomment*/ 1 2 3');
%! a = strread (str, '%f', 'commentstyle', 'c');
%! assert (a, [1; 2; 3]);
------------------------------------------------------------------------------
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