How do i create a multi-colour histogram using excel data?

Hi, I tried to make a histogram same as the picture below. The yA, yB, yC are the data which i exported from excel. However, i got the error message at the end:

1) Error using horzcat

Dimensions of arrays being concatenated are not consistent.

2) Error in Untitled (line 20)

yA2 = [yA minY maxY];

What have i done wrong?

clf
clear all
clc

% x  = x values for yA and yB (not needed for histogram)
% yA = data set A
% yB = data set B
% nBins = number of bins to use in histograms

% yA=30mins, yB=120mins, yC=240mins
Load yA
Load yB
Load yC

% Set extrema
minY = 0; %there are no values lower than this
maxY = 50; %there are no values higher than this

% Add in extrema placeholders to adjust bins to a common scale
yA2 = [yA minY maxY];
yB2 = [yB minY maxY];
yC2 = [yC minY maxY];

% Bin data
[countsA2, binsA2] = hist(yA2, nBins);
[countsB2, binsB2] = hist(yB2, nBins);
[countsC2, binsC2] = hist(yC2, nBins);

% Remove extrema placeholders from counts
histEnds = zeros(size(binsA2));
    %data sets A and B have the same nBins, so binsA2 and binsB2 are same length
histEnds(1) = 1; %removes minimum placeholder
histEnds(end) = 1; %removes maximum placeholder

countsA3 = countsA2 - histEnds;
countsB3 = countsB2 - histEnds;
countsC3 = countsC2 - histEnds;

% Plot histograms
hold all
bar(binsA2, countsA3, 'b')
bar(binsB2, countsB3, 'r')
bar(binsC2, countsC3, 'g')
hold off

% Labels
set(gca, 'XLim', [minY maxY])
xlabel('y value')
ylabel('counts')
legend({'A', 'B', 'C'})

Answer 1

[J. Alex Lee]

I suspect your yA, yB, yC are column vectors, which you are trying to horizontally concatenate with scalars. You can probably fix this error by

yA2 = [yA;minY;minX]

But, I think you are making your script too complicated; don't alter you data to fit end visualization goals, but rather look for options in your tools to do that.

% Load yA
% Load yB
% Load yC

% comment out below 3 lines and uncomment your original data loads above
yA = randn(1000,1)*7+15;
yB = randn(1000,1)*3+7;
yC = randn(1000,1)*4+30;

% specify number of bins and edges of those bins; this example evenly spaces bins
NumBins = 25;
BinEdges = linspace(0,50,25);
% use histcounts and specify your bins
cntA = histcounts(yA,'BinEdges',BinEdges);
cntB = histcounts(yB,'BinEdges',BinEdges);
cntC = histcounts(yC,'BinEdges',BinEdges);
% plot
figure(1); cla; hold on;
% convert bin edges into bin centers
b = BinEdges(1:end-1)+diff(BinEdges)/2
% use bar
bar(b,[cntA',cntB',cntC'],'stacked')

[J. Alex Lee]

Edited first answer to correct some bugs.

Answer 2

[ka chun yick]

Hi,

This is my updated script. But it still got some problems at the end:

Undefined function or variable 'nbins'.

Error in Untitled (line 20)

[countsA2, binsA2] = hist(yA2,nbins);

clf
clear all
clc
% x  = x values for yA and yB (not needed for histogram)
% yA = data set A
% yB = data set B
% nBins = number of bins to use in histograms
% yA=30mins, yB=120mins, yC=240mins
load yA
load yB
load yC
% Set extrema
minY = 0; %there are no values lower than this
maxY = 50; %there are no values higher than this
% Add in extrema placeholders to adjust bins to a common scale
yA2 = [yA;minY;maxY];
yB2 = [yB;minY;maxY];
yC2 = [yC;minY;maxY];
% Bin data
[countsA2, binsA2] = hist(yA2,nbins);
[countsB2, binsB2] = hist(yB2,nbins);
[countsC2, binsC2] = hist(yC2,nbins);
% Remove extrema placeholders from counts
histEnds = zeros(size(binsA2));
    %data sets A and B have the same nBins, so binsA2 and binsB2 are same length
histEnds(1) = 1; %removes minimum placeholder
histEnds(end) = 1; %removes maximum placeholder
countsA3 = countsA2 - histEnds;
countsB3 = countsB2 - histEnds;
countsC3 = countsC2 - histEnds;
% Plot histograms
hold all
bar(binsA2, countsA3, 'b')
bar(binsB2, countsB3, 'r')
bar(binsC2, countsC3, 'g')
hold off
% Labels
set(gca, 'XLim', [minY maxY])
xlabel('y value')
ylabel('counts')
legend({'A', 'B', 'C'})

[J. Alex Lee]

The error sounds straightforward...you have not defined nBins.

Does my solution not work?

Answer 3

[ka chun yick]

Hi,

I still got a problem on the line 20, bar(b,[cA',cB'],'stacked'), any thought?

[J. Alex Lee]

Yea, my bad. I was incomplete in my last line. Here's a tested example with test data.

% Load yA
% Load yB
% Load yC

% comment out below 3 lines and uncomment your original data loads above
yA = randn(1000,1)*7+15;
yB = randn(1000,1)*3+7;
yC = randn(1000,1)*4+30;

% specify number of bins and edges of those bins; this example evenly spaces bins
NumBins = 25;
BinEdges = linspace(0,50,25);
% use histcounts and specify your bins
cntA = histcounts(yA,'BinEdges',BinEdges);
cntB = histcounts(yB,'BinEdges',BinEdges);
cntC = histcounts(yC,'BinEdges',BinEdges);
% plot
figure(1); cla; hold on;
% convert bin edges into bin centers
b = BinEdges(1:end-1)+diff(BinEdges)/2
% use bar
bar(b,[cntA',cntB',cntC'],'stacked')

But note that the error message told you exactly what was wrong.

Answer 4

[ka chun yick]

Thanks, it works. In additional, i would like to add a distribution fit. I looked at the tutorial: https://uk.mathworks.com/help/stats/histfit.html

histfit(data) plots a histogram of values in data using the number of bins equal to the square root of the number of elements in data and fits a normal density function.

So, hisfit(data) will do its work. How do i add this line to the script?

% Load yA
% Load yB
% Load yC
% comment out below 3 lines and uncomment your original data loads above
yA = randn(1000,1)*7+15;
yB = randn(1000,1)*3+7;
yC = randn(1000,1)*4+30;
% specify number of bins and edges of those bins; this example evenly spaces bins
NumBins = 25;
BinEdges = linspace(0,50,25);
% use histcounts and specify your bins
cntA = histcounts(yA,'BinEdges',BinEdges);
cntB = histcounts(yB,'BinEdges',BinEdges);
cntC = histcounts(yC,'BinEdges',BinEdges);
% plot
figure(1); cla; hold on;
% convert bin edges into bin centers
b = BinEdges(1:end-1)+diff(BinEdges)/2
% use bar
bar(b,[cntA',cntB',cntC'],'stacked')

[J. Alex Lee]

I don't have the toolbox. It seems you already have the full documentation, why not use it?

[ka chun yick]

Hi,

I am using the academic version so i don't have the access of toolbox. Any idea that i can add the histfit()to the existing sctipt? I am not sure which line should i define....