How to find the quartiles of an array?

I currently have a 1024x1024 array. I want to find the first and fourth quartile range for this array. (I already used iqr(a(:)) to find the interquartile range, however now I want to find the first and fourth). Thank you!

Answer 1

[Rajanya]

Hi @RB,

You can use 'prctile' on the flattened array to calculate the 25th percentile which in turn will give you the first quartile.

a = rand(1024,1024);
a_flattened = a(:);
out = prctile(a_flattened,25)

out = 0.2505

You can refer to the documentation page of 'prctile' for more information on the same by executing the following command from MATLAB command window.

doc prctile

Thanks!