# how to make intervals in a bar graph

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Sadiq Akbar on 21 Oct 2020
Commented: Sadiq Akbar on 23 Oct 2020
Suppose I have some people and they are of different weight, e.g.
weight in Kq: 40-45 45-50 50-55 55-60 60-65
No. of Persons: 4 12 13 6 5
I want to represent the weight on x-axis and No. of persons on y-axis. This will tell us that there are 4 persons whose weight lies within 40-45 and 12 persons whose weight lies in the interval 45-50 kilo and so on. How can we do that?

Adam Danz on 21 Oct 2020
Edited: Adam Danz on 21 Oct 2020
For continuous intervals
Since your intervals are continuous, you should be using histogram() instead of bar().
kg = 40:5:65;
n = [4 12 13 6 5];
histogram('BinEdges',kg,'BinCounts',n)
xlabel('Weight (kg)')
ylabel('Number of participants')
For discountinuous or categorical intervals
For any future visitors who are not using continuous x-bins and want to label bin edges, follow this demo.
% Create data
bins = [10 20;
50 60;
75 85];
y = [20;10;30];
% Create bar plot
% The .5 specifies bin width, making room for labels
h = bar(y, .5);
% Get bar centers and bar widths
xCnt = h.XData + h.XOffset; % XOffset is undocumented!
width = h.BarWidth;
% Get x-val of bar-edges
barEdgesX = xCnt + width.*[-.5;.5];
% Set new xtick and xticklabels, rotate by 90deg.
ax = h.Parent; % axis handle, if you don't have it already
ax.XTick = barEdgesX(:);
ax.XTickLabel = string(reshape(bins',[],1));
ax.XTickLabelRotation = 90;
##### 2 CommentsShowHide 1 older comment
Adam Danz on 21 Oct 2020
Oh, that's interesting!
Thanks for the idea, the cyclist.
I just tested it with NaNs as spacers too but histogram throws an error that N must be finite.

the cyclist on 21 Oct 2020
Edited: the cyclist on 21 Oct 2020
Here is one way:
w = 42.5 : 5.0 : 62.5;
n = [4 12 13 6 5];
bar(w,n,'BarWidth',1)
FYI, if you have the underlying individual weight data, rather than the bin counts, you will definitely want to use histogram as in Adam's solution (although the syntax will be different).
Sadiq Akbar on 23 Oct 2020
I found one such code on this site today. The code is as follows:
[~,edges] = histcounts(log10(x));
histogram(x,10.^edges)
set(gca, 'xscale','log')
In this code, when I replace x by my data, then it plots well. Now I want to insert a preview in this graph. How can I insert the same graph as a preview pane in the same figure window as is in the attachment figure.