# Randomizing the picking and changing of values in a 3D array

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Filip Hansson on 16 Aug 2022
Commented: Filip Hansson on 18 Aug 2022
I have a 24x365x60 array and would like to set 4 of the 24 values for each of the 365 columns to a constant (11), based on a 24x365 matrix with "1"s in the particular positions, for a randomized 30 of the 60 sheets (third dimemsion) and letting the other 30 beeing unchanged. What is the best way to solve this?

Jan on 16 Aug 2022
Edited: Jan on 17 Aug 2022
x = zeros(24, 365, 60);
m3 = randperm(60, 30);
for i3 = m3
for i2 = 1:365
m1 = randperm(24, 4);
x(m1, i2, i3) = 11;
end
end
sum(x(:) == 11)
ans = 43800
Is this the wanted number of 11's? 4*365*30 = 43800
Filip Hansson on 18 Aug 2022
I saw the solution from you in another tread and it worked lika a charm!

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