Random order of rows Matlab
Say we have a matrix of size 100x3
How would you shuffle the rows in开发者_Python百科 MATLAB?
To shuffle the rows of a matrix, you can use RANDPERM
shuffledArray = orderedArray(randperm(size(orderedArray,1)),:);
randperm
will generate a list of N
random values and sort them, returning the second output of sort
as result.
This can be done by creating a new random index for the matrix rows via Matlab's randsample function.
matrix=matrix(randsample(1:length(matrix),length(matrix)),:);
While reading the answer of Jonas I found it little bit tough to read, tough to understand. In Mathworks I found a similar question where the answer is more readable, easier to understand. Taking idea from Mathworks I have written a function:
function ret = shuffleRow(mat)
[r c] = size(mat);
shuffledRow = randperm(r);
ret = mat(shuffledRow, :);
Actually it does the same thing as Jonas' answer. But I think it is little bit more readable, easier to understand.
For large datasets, you can use the custom Shuffle function
It uses D.E. Knuth's shuffle algorithm (also called Fisher-Yates) and the cute KISS random number generator (G. Marsaglia).
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