How to generate sample Randomly in Matlab

Hello everyone i hope you are doing well.

I have the following code which generate 4000 sample for a value of 200. and output is the if 1x4000

I want the value to be random from 1 to 1000. and save the result of each value in seperate row

for example value=1 it has 4000 samples in first row, after value=100 it has 4000 samples in second row

value= [200];
Numberofsample = [4000];
output = repmat(value,1,(ceil(sum(Numberofsample)/length(Numberofsample))));

Answer 1

[Benjamin Thompson]

>> output = randn(1,4000);

>> size(output)

ans =

1 4000

[Med Future]

@Benjamin Thompson no Sir, i want to be random value on y(axis) like levels and 4000 are the samples

[Benjamin Thompson]

Are you creating a plot where some data is the x axis values (not random, if so what is it) and the random values are on the y axis?

Or if you are just asking for the result to be a column vector instead of a row vector, swap the order of arguments to randn.

[Med Future]

@Benjamin Thompson x axis has number of samples=4000

and y is the random values between 1 to 1000

[Benjamin Thompson]

You use randi for a uniform distribution over a specific range, and then plot to plot the results:

>> output = randi(1000,1,4000);

>> figure, plot(1:4000,output);

[Med Future]

@Benjamin Thompson you dont understand my point. you are doing wrong

[Med Future]

The above code output is like that.

I want to have random values on y axis like i have only 200 now

and save the values in seperate row

[Benjamin Thompson]

If you are looking for a row vector containing the same random number repeated 1000 times, that would be:

output = randi(100, 1,1) * ones(1,1000);

If this is not what you want please try some of these examples and see if you can make it look the way you want. If you have more problems please ask a question with more information, perhaps a small example of the larger data set you want to create.

[Walter Roberson]

value = [1, 100, 200];
output = repmat(randi(1000, 1, 4000), length(value), 1);

[Med Future]

@Walter Roberson not like that. let me explain it again.

i want a random value which is remain same for 4000 samples in 1 row

then second random value which is remain same for 4000 save in 2 row so on.

[Walter Roberson]

value = [1, 100, 200];
output = repmat(randi(1000, length(value), 1), 1, 4000);

[Med Future]

@Walter Roberson Thanks for the answer.

I have to generate the data for other classes as well. Can i post another question?

[Walter Roberson]

The method remains the same. Take one random quantity for each "value" and repeat it out to the 4000 or whatever you need.

If the class data is quantized, then you can use a random integer in the range of 1 to the number of quantized values, and use that to index the original data, like

output = repmat( MyCategories(randi(length(MyCategories),  length(value), 1), 1, NumberOfCopies);