How to set the 'DisplayName' properties for a bar chart with multiple sets of bars directly from the call to 'bar', not using 'set' afterwards

This questions is similar to the ones at the links below (which were never answered satisfactorily).

https://stackoverflow.com/questions/53741727/get-legend-right-with-stacked-bar-plot

https://uk.mathworks.com/matlabcentral/answers/476496-how-could-i-set-the-legend-for-a-particular-bar-in-a-bar-chart

Why can I use the 'set' command to set the bar chart 'DisplayName' properties for a bar chart with multiple groups of bars, but attempting to set the exact same DisplayName when calling bar throws an error?

To use the solution from the mathworks link:

% This will produce 4 groups of 3 different colored bars
y = [2 2 3; 2 5 6; 2 8 9; 2 11 12];
h = bar(y);  % h will have 3 handles, one for each color of bars
% set 3 display names for the 3 handles
set(h, {'DisplayName'}, {'Jan','Feb','Mar'}')
% Legend will show names for each color
legend() 

This works fine. But attempting to set the 'DisplayName' from 'bar' directly throws an error.

% This will produce 4 groups of 3 different colored bars
y = [2 2 3; 2 5 6; 2 8 9; 2 11 12];
h = bar(y, {'DisplayName'}, {'Jan','Feb','Mar'}');  % h will have 3 handles, one for each color of bars

Error using matlab.graphics.chart.primitive.Bar
Value cell array handle dimension must match handle vector length.

Error in bar (line 223)
h(i) = matlab.graphics.chart.primitive.Bar('Parent',hPar,...

legend() 

This strikes me as poor design.

[Dyuman Joshi]

"but attempting to set the exact same DisplayName when calling bar throws an error?"

Because the expected input to the property DisplayName is a character vector or a string scalar, whereas you have provided a cell array of character vectors.

https://in.mathworks.com/help/matlab/ref/matlab.graphics.chart.primitive.bar-properties.html#d126e88107

When using the bar() call, DisplayName is expected to be used for when the output is a single bar object.

In case of multiple bar objects as the output, you will have to use other approachs, like using set() (as you did above) or legend() -

y = [2 2 3; 2 5 6; 2 8 9; 2 11 12];
h = bar(y)

h = 
  1×3 Bar array:

    Bar    Bar    Bar

arr = {'Jan','Feb','Mar'};
legend(arr)

Answer 1

[Hassaan]

As per my understanding and the working code you shared. It's essential to understand that the syntax you attempted to use directly within the bar function call for setting DisplayName properties is not supported. The correct way to set the DisplayName for each group of bars for the purpose of having a legend is to first create the bar chart and then separately set the DisplayName for each group using the handles returned by the bar function.

% Data for the bar chart
y = [2 2 3; 2 5 6; 2 8 9; 2 11 12];

% Create the bar chart
h = bar(y);  % h will have 3 handles, one for each color of bars

% Set 3 display names for the 3 handles, corresponding to each group of bars
set(h(1), 'DisplayName', 'Jan');
set(h(2), 'DisplayName', 'Feb');
set(h(3), 'DisplayName', 'Mar');

% Create a legend to show names for each color
legend();

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