MATLAB: Is it a bug

bugMATLABstr2num

str2num('"abc"')
ans = 
    "abc"

Best Answer

I call this a bug.

My comments

The old function, str2num(), uses eval() to do the conversion. "Eval is evil" or at least tricky to use. See https://se.mathworks.com/matlabcentral/answers/51946-systematic-do-not-use-global-don-t-use-eval#answer_63393
The data type, string, is new.
str2num('"abc"') is a clever test case, which I assume is not in their test suite.

The last lines of str2num() read

if ischar(x) || iscell(x)
   x = [];
   ok = false;
end

Adding || isstring to the condition solves the problem - I think.

Related Solutions

MATLAB: How to convert string with complex numbers to matrix

E.g. simple code assuming no blanks in the numbers,

S = '5+6i 3-2i 1-i @ 4+i 2-0.2i 2.5-1.3i @'
S(S=='@') = ';';
x = find(S=='=',1);
if( isempty(x) )
    x = 0;
end
eval([S(1:x) '[' S(x+1:end) ']'])
ans =
   5.0000 + 6.0000i   3.0000 - 2.0000i   1.0000 - 1.0000i
   4.0000 + 1.0000i   2.0000 - 0.2000i   2.5000 - 1.3000i

MATLAB: Check if a number of varibles in a function satifies a condition.

There are already tools for performing these tasks. Check out the InputParser class [ ref, ref ]. It will allow you to declare three sets of arguments: required, optional, and param/value pairs. For each parameter, you will be able to define a check function, as well as a default value for all but required parameters.

EDIT: just as an example, here is the beginning of a function using an input parser

 function [hFig, hAxis, hLegend, hPatches] = bar_varWidth( colWidth, ...
    data, varargin )
    % --- 1. Parse input parameters.
    parser = inputParser ;
    parser.StructExpand  = true ;
    parser.CaseSensitive = false ;
    parser.addRequired( 'colWidth', @isnumeric ) ;
    parser.addRequired( 'data', @isnumeric ) ;
    parser.addParamValue( 'legend', [], @(x) ischar(x) || iscell(x)  ) ;
    parser.addParamValue( 'xTickLabel', [], @(x) isnumeric(x) || iscell(x)  ) ;
    parser.addParamValue( 'xTickLabelFormat', '%.2f', @ischar ) ;
    parser.addParamValue( 'xTickLabelShiftThreshold', 10, @isnumeric ) ;
    parser.addParamValue( 'xTickLabelAngle', 90, @isnumeric ) ;
    parser.addParamValue( 'xTickLabelLineLength', [], @isnumeric ) ;
    parser.parse( colWidth, data, varargin{:} ) ;
    args = parser.Results ;
    % --- 2. ...

and here all parameters are accessible as fields of args, e.g.

    args.colWidth
    args.legend

Best Answer

Related Solutions

MATLAB: How to convert string with complex numbers to matrix

MATLAB: Check if a number of varibles in a function satifies a condition.

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