I want to randomly have numbers added to a matrix

I have a 300x300 zeros matrix and I want to have numbers between 0 and 1 (inclusive) randomly placed amongst the matrix, the numbers can be repeated (and ideally will be repeated completely randomly). Any help would be great.

Answer 1

[KSSV]

A = round(rand(300,300)) ;

or

A = randi([0 1],300,300)

Answer 2

[Star Strider]

Use the randi function:

M = randi([0 1],300);

[Daniel Gray]

Hi, this randomaly places 0's and 1's, is there a way to randomly places numbers between 0 and 1 inclusively?

[KSSV]

That case you should use rand

[Jan]

X = rand(300, 300);

KSSV and Star Strider have suggested randi and rand already. Although the code did not solve your problem completely, the hints are useful already: Read the documentation of the suggested commands to find out, how to use them such, that it satisfies your need. The "See also" lines on the bottom of the docs are very valuable.

I suggest to use the forum not only as a service for complete solutions, but to consider all details mentioned here to improve your own Matlab skills.

In German this is called "mitdenken", but I cannot translate this to English. It doubles the power of the given answers. :-)

Answer 3

[Image Analyst]

This will do it:

% Create a matrix of all zeros
m = zeros(300, 300);
% Get locations for random changes
% Define the number of random numbers you want placed.
numRandomNumbers = round(.3 * numel(m)); % For example 30%
% Get their locations, randomly arranged.
linearIndexes = randperm(numel(m), numRandomNumbers);
% Assign random numbers to those locations
m(linearIndexes) = rand(1, numRandomNumbers);
imshow(m)