Display comma as decimal digits separator in simple 2D plots

Is it possible in a simple 2D plot display numbers with comma as decimal digits separator instead of the dot?

Maybe is there a label to add in the xtickformat command?

Answer 1

[Walter Roberson]

No, the only way to do that is to build a TickLabels cell array of character vectors, or string object array, containing the characters you want to be displayed.

[Walter Roberson]

ax = gca;
ax.XTickLabels = strrep(cellstr(num2str( ax.XTick(:) )),'.',',');

[Karsten Opel]

This works fine, but be aware of a possible pitfall: If you resize your figure causing a change in the number of ticks, the tick labelling will not reflect these changes correctly.

[Walter Roberson]

@Karsten Opel is correct: the above code changing the XTickLabels property needs to be done each time the number or position of ticks is changed. If you are working with tradtional figures, this might involve using a SizeChangedFcn (or ResizeFcn) callback at the figure or uipanel level; unfortunately there is no similar callback at the axes level.

To work at the axes level, you might need to do something like add a listener for PostSet on the XTicks property -- or perhaps on the XRuler Ticks property.

Answer 2

[Roofus Milton]

This is possible by calling the .NET Framework string formatting functions. Without getting into a discussion of Cultures in the Framework, I have provided a simple function which provides the format.

NumberFormatMatlabAnswers([1000:1010]', 4, 'decimalSeparator', ',', 'numberGroupSeparator', '.')

function output = NumberFormatMatlabAnswers(nums, varargin)
    
    % initialize the inputParser
    ip = inputParser;
    
    % add function parameters to inputParser
    addRequired(ip, 'nums');
    addOptional(ip, 'decimals', 2);
    addParameter(ip, 'decimalSeparator', '.');
    addParameter(ip, 'numberGroupSeparator', ',');
    
    % validate the parameters
    parse(ip, nums, varargin{:});
    
    % create the .NET object to store format specifics
    numFormatInfo = System.Globalization.NumberFormatInfo();
    
    % pass the custom format specifics to their respective object properties
    numFormatInfo.NumberDecimalSeparator = ip.Results.decimalSeparator;
    numFormatInfo.NumberGroupSeparator = ip.Results.numberGroupSeparator;
    
    % initialize the output cell array
    output = cell(length(ip.Results.nums), 1);
    
    % create the format string for .NET
    formatString = strcat('{0:N', num2str(ip.Results.decimals), '}');
    
    for p = 1:length(ip.Results.nums)
        
        % get the formatted string from .NET
        output{p} = char(System.String.Format(numFormatInfo, formatString, ip.Results.nums(p)));
        
    end
    
end

[Walter Roberson]

And you would then have to pass output as the appropriate tick labels -- the above does not change how axes tick labels are constructed.

Answer 3

[Elia Sironi]

Thank you to both of you. Walter's suggestion does exactly what I was searching!