Lettering a Bar Chart

I want to create a bar chart and label my XAxis in letters for as many bars as there are. For example if I have 4 bars I want them to be individually labeled A, B, C, D and I want it to work for any amount of bars. I know using sprintf with %d will do what I want with numbers and I thought that using %s or %c would do what I wanted with letters, but it's just returning empty character boxes. What do I have to change to print letters instead?

    yData = [10, 25,15,10,25,20]
    
    myFig = gcf; 
    myAx = axes(myFig);
    
    myPlot = bar(myAx, yData);
   
    myAx.Title.String = 'Data Visualization';
    myAx.YLabel.String = 'Value';
    myAx.XLabel.String = 'Category';
    myAx.YLim = [0 30];
    
    endAt = length(myAx.XAxis.TickLabels);
    
    for i = 1:endAt
        
        myAx.XAxis.TickLabels{i} = sprintf ('%d' , i)
        
    end 
   

Answer 1

[the cyclist]

Here is one way, closely based on yours:

    yData = [10, 25,15,10,25,20];
    
    myFig = gcf; 
    myAx = axes(myFig);
    
    myPlot = bar(myAx, yData);
   
    myAx.Title.String = 'Data Visualization';
    myAx.YLabel.String = 'Value';
    myAx.XLabel.String = 'Category';
    myAx.YLim = [0 30];
    
    endAt = length(myAx.XAxis.TickLabels);
    
    for i = 1:endAt
        
        myAx.XAxis.TickLabels{i} = sprintf ('%s' , char(i-1+'A'));
        
    end 

Note my changes inside sprintf.

But you don't need a for loop for the labeling:

    set(gca,'XTickLabel',char((0:endAt-1) + 'A')')

Answer 2

[Adam Danz]

It's better to avoid setting tick labels when possible.

Instead, use a categorical variable (xCats) for x, defined by letters starting with A to however many values are in yData.

yData = [10, 25,15,10,25,20];

xCats = categorical(num2cell(char((0:numel(yData)-1)+'A')));
myFig = gcf;
myAx = axes(myFig);
myPlot = bar(myAx, xCats, yData);

[the cyclist]

@Adam Danz makes a great philosophical programming point. Since 'A', 'B' , etc are presumably referencing the data themselves, it is better to reflect that in the data, not just the labels.

It's a little bit of a lazy quirk of MATLAB (and other languages) that it allows the programmer to make a bar chart by specifying only the y-data -- and then adds the probably-wrong numeric x-labels automatically.

It's a shame that the creation of the vector {'A','B', ..., arbitrary length} is a bit awkward, because this is truly the better way to go.