cellfun changes in R2017b

Question

Nathan Calvert 2018-7-27

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/412461-cellfun-changes-in-r2017b

评论： Steven Lord 2018-7-27

I am trying to use cellfun in the following context but it's giving an error "Undefined variable it or class (it)":

% Convert struct of interp_tables to cell array if isstruct(it) it = struct2cell(it); end

% Process filename pattern
tokens  = regexp(pattern,'<([^>]+)>','match');
etokens = strrep( tokens,'$i','i');
etokens = strrep(etokens,'$v','$v1');
etokens = strrep(etokens,'$d','$d1');
etokens = regexprep(etokens,'\$v(\d+)','it{i}.variable_names{$1}');
etokens = regexprep(etokens,'\$d(\d+)','it{i}.dimension_names{$1}');
% Write to file 
for i = 1:numel(it)
  token_vals = cellfun(@(x) num2str(eval(x(2:end-1))),etokens,'uniform',false);
  file = strrep(pattern,tokens,token_vals);
  it{i}.to_file(file{1},varargin{:});
end

It works in the previous versions of Matlab but changes to the built-in cellfun break it here. Is there a work-around?

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Answer 1

Philip Borghesani 2018-7-27

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/412461-cellfun-changes-in-r2017b#answer_330694

There was no change to cellfun. You are (were?) misusing eval inside of an anonymous function, In R2015b and later MATLAB will not let you get away with it. Copied directly from the help page:

Use only explicit variables when constructing anonymous functions. If an anonymous function accesses any variable or nested function that is not explicitly referenced in the argument list or body, MATLAB throws an error when you invoke the function. Implicit variables and function calls are often encountered in the functions such as eval, evalin, assignin, and load. Avoid using these functions in the body of anonymous functions.

There are tricks that will allow it to be seen in the eval but you are much better off re-coding this in a way that does not use eval.