# Change histogram y-axis to percentage [R2017b]

636 views (last 30 days)
TJ on 17 Jan 2018
Edited: Lisa Kinsale on 28 Jan 2021
Good morning,
I have used the histogram function to get a plot of a histogram. Specifically, for presentation, I would actually only like to have the probability value as a percentage plotted against the bins. For this I have used the histogram properties 'Normalisation' set to 'probability' and 'DisplayStyle' set to stairs'. I need the y-axis as a percentage. I see that I cannot access the histogram.Data values as they are read only and therefore I cannot modify them. I was simply going to multiply them by 100.
Is there anyway to plot this data from the histogram function as: 1) a line plot; 2) with y-axis values as percentage so that when I zoom in and out the percentage also re-scales rather than just setting yticklabels.
Cheers, TJ

Star Strider on 17 Jan 2018
I’m not certain what you’ve already done.
The 'YTick' values are available, and you can modify them as you would with any other usual axis object.
Example
d = randn(1, 1000); % Create Data
figure
histogram(d, 50, 'Normalization','probability', 'DisplayStyle','stairs')
figure
histogram(d, 50, 'Normalization','probability', 'DisplayStyle','stairs');
ytix = get(gca, 'YTick')
set(gca, 'YTick',ytix, 'YTickLabel',ytix*100)
Compare the two figures to see the result of recalculating the 'YTick' values in the second histogram.

Andreas Vester on 8 Mar 2018
Browse the MATLAB documentation for 'yticks' and 'yticklabels'.
One solution might be as follows:
yticklabels(yticks*100)
Lisa Kinsale on 28 Jan 2021
Thank you, this works,
Additionally do you know how to display the percentage sign (%) on the new yticklabels?

Tony Castillo on 17 Apr 2020
Hi Sir,
I have plotted a histogram I wonder if is possible to set another axis in the plot like the one in the figure attached, would you mind telling me how to do it, please?. Mahmoud Alkhateb on 17 Sep 2020
Hi Tony!
if you want to have the relative frequency on the y-axis (precentage).
You can try this one:
Let's say you have this:
x = let's say you have 30 values bewteen 0 and 25.
L = define the bins you wanna have. e.g. L = 0:5:25; %% this will give you bins that are equal to five starting at 0 and ending at 25.
Now you can plot your histogram as follows
bar (x, histc(x,L)/30, 'histc') %% dividing by 30 which is the number of the total values you have, will give you the relative frequency to evey bin.
Let's say you got 6 values between 0 and 5 (the first bin), what you will get at the y-axis for this bin is 6/30 which is 0.2 (which is 20 %).
I hope this helped!