Clear Filters
Clear Filters

How do I create a single random number between two values?

138 views (last 30 days)
I need to create a value for one of my variables in a loop which will run ten times. I need it to be between two set values, e.g. 1e3 and 9e3. Sorry for what is probably a very basic question but I am new to matlab.

Accepted Answer

Wayne King
Wayne King on 22 Mar 2012
Does it have to be an integer, or any number between 1e3 and 9e3?
For the former:
Int = randi([1e3 9e3],1,1);
For the latter:
R = 1e3+8e3*rand(1,1);
The preceding line gives you a uniform random number between 1e3 and 9e3.
  4 Comments
Marvin
Marvin on 22 Mar 2012
Thanks, I tried changing the seed and it didn't seem to work, the problem was that I was changing the seed at the beginning of the program, not inside the loop! Silly mistake. Thanks for all the help!

Sign in to comment.

More Answers (3)

Image Analyst
Image Analyst on 22 Mar 2012
The help facility is always a good place to start. If you had searched the help for rand, you would have seen the very first example:
Example 1
Generate values from the uniform distribution on the interval [a, b]:
r = a + (b-a).*rand(100,1);
  6 Comments
Image Analyst
Image Analyst on 13 Mar 2023
@Andrew Sol Since they will not be there (infinitesimally small chance) if you're just getting random numbers, you will have to add them in manually: Somthing like:
% Generate values from the uniform distribution on the interval [a, b]:
a = 5;
b = 10;
numElements = 7;
r = a + (b-a).*rand(numElements,1);
% Add in the max and min
r = [a; b; r];
% Scramble the array so they are not at the beginning
scrambledIndexes = randperm(numel(r));
r = r(scrambledIndexes)
r = 9×1
7.1316 10.0000 9.8263 6.0645 6.5554 7.7677 7.3234 5.0000 5.1012
Andrew Sol
Andrew Sol on 13 Mar 2023
@Image Analyst Thank you very much for your answer! it's really not that complicated

Sign in to comment.


Aldin
Aldin on 22 Mar 2012
It's very helpful.

Nisha Bharti
Nisha Bharti on 12 Jan 2022
To generate a random number between [a,b]:
r = a + (b-a)*rand();
To generate N numbers:
r = a + (b-a)*rand(1,N);

Categories

Find more on Creating and Concatenating Matrices in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!