Plotting histogram with percentage

Hi all,

Recently I had a csv that I want to import by

T = readtable('1.csv');

and plot by histogram

Any chance to display this histogram with indivudual percentage over each bar?

Class; Value; Class start; Class end;
1;8410;-0.039916738868;-0.032423677233;
2;78271;-0.032423677233;-0.024930615599;
3;501926;-0.024930615599;-0.017437553965;
4;149453;-0.017437553965;-0.009944492330;
5;342924;-0.009944492330;-0.002451430696;
6;546900;-0.002451430696;0.005041630939;
7;537726;0.005041630939;0.012534692573;
8;527320;0.012534692573;0.020027754207;
9;478488;0.020027754207;0.027520815842;
10;345973;0.027520815842;0.035013877476;
11;276272;0.035013877476;0.042506939111;
12;694253;0.042506939111;0.050000000745;

Answer 1

[Rik]

You will have to insert those labels with the text function.

[Thinkboard]

Any chance to annotate t automaticaally?

[Rik]

If that would be possible it would be in the documentation. So, no.

If you have trouble implementing it, feel free to post a comment with what you tried.

[Adam Danz]

Now all you need are the x-values that define the center of each bar and the y values that define the height of each bar.

xCenters = h.BinEdges(1:end-1) + h.BinWidth/2; 
yHeights = h.Values;

Then calculate the percentages

percentages = .... % I'll leave that up to you.
% There needs to be n values where n is the number of bars. 

Convert the percentages to strings with 1 decimal place

percentageStrings = compose('%.1f',percentages*100); 

Then label the peaks

text(xCenters,yHeights,percentageStrings,...
    'HorizontalAlignment','center','VerticalAlignment','middle', ...
    'FontSize', 8); 

[Thinkboard]

Hi Rik,

I've found a useful code here on data exchange.

But my main graph is using bar(X,Y) plot instead of historgram, how can i make use of percent generate from "Histogram Percentage function" to add it on my bar chart?

clear;
close all;

Array=csvread('1.csv',1,0);
Value = Array(:,2);
CStart = Array(:,3);
CEnd = Array(:,4);
edges = transpose(CStart);

figure;
subplot(2,1,1);
bar(edges,Value)
title('Histogram');
xlabel('Distnce');
ylabel('Count');

subplot(2,1,2);
histogramPercentage(Value);
title('Histogram Percentage')
xlabel('Values');
ylabel('Number of Observations');

[Rik]

You can either use the code Adam suggested, or look into what that function from the FEX is actually doing:

function histogramPercentage(x,fontSize)
h =  histogram(x,'Visible', 'off');
[nelements,centers]= hist(x,h.NumBins);
percantages = 100 * nelements / sum(nelements);
bar(centers,nelements,'Facecolor',[0.4,0.7,0.9],'BarWidth',1);
for k = 1:numel(centers)
    if percantages(k) ~= 0
        text(centers(k),nelements(k),[sprintf('%.f',(percantages(k))) '%'],'HorizontalAlignment','center','VerticalAlignment','bottom','FontSize',fontSize);
    end
end

So in short: you need the bin centers and the height. Then you can easily create the text objects in a loop.

[Adam Danz]

Bin centers for bar chart can be computed using this appoach.

https://www.mathworks.com/matlabcentral/answers/462532-multi-bar-labeling-plot#answer_375379