randomly select elements of an array
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Hi How i can select randomly elements from a matrix o array
I have the matrix and i want to select "x" numbers of elements
thanks
采纳的回答
Walter Roberson
2012-4-12
msize = numel(YourMatrix);
idx = randperm(msize);
YourMatrix(idx(1:x))
If you have a fairly new version of MATLAB, you can instead use
msize = numel(YourMatrix);
YourMatrix(randperm(msize, x))
10 个评论
Noe alvarado
2012-4-12
Noe alvarado
2012-4-12
Sourav Mondal
2012-10-10
>> A=[1 2 3; 4 5 6; 7 8 9]
A =
1 2 3
4 5 6
7 8 9
>> N=2; >> B=A((1:N),:)
B =
1 2 3
4 5 6
bkshn
2014-4-15
Hello Walter Roberson
If I want to find a random element in one row of a matrix, Could you help me How can I do?
For example I want to select a random element in last row of a matrix.
Walter Roberson
2014-4-15
YourMatrix(end,randperm(size(YourMatrix,2), 1))
feit feit
2020-11-30
Hi Walter Roberson,
I want to select a random element from a column, for example from Column 1 or Column 2 or Column 3. Would you help me with the code?
Thank you!
Walter Roberson
2020-11-30
YourMatrix(randi(size(YourMatrix,1)), ColumnNumber)
feit feit
2020-12-2
Thank you, Walter!
Jaime Gurrola
2020-12-7
Hi walter, i want to select a random element from this array, help please
A={'Yellow','Green','Blue','Orange','Black','Grey','Red','Brown','Purple','White'};
Walter Roberson
2021-9-3
A{randi(numel(A))}
更多回答（2 个）
Prasobhkumar P. P.
2020-7-28
编辑：Walter Roberson
2021-9-3
histHandle= histfit(data,nBins,'normal');
[Val Ind] = max(histHandle(2).YData); %histHandle(2) corresponds to the curve fitted
M = histo18(2).XData(Ind);
Use "randsample"
For array:
Arry = [1 4 5 7 8 9];
Smpl = randsample(Arry, 3)
For strings:
Arry = ["Yellow" "Green" "Blue" "Orange" "Black" "Grey" "Red" "Brown" "Purple" "White"];
Smpl = randsample(Arry, 2)
How do you want to sample the matrix? If its any element, just convert to array (e.g. Mat(:)). Otherwise you have to apply the function to each row/column separately.
3 个评论
Walter Roberson
2021-9-3
Note: randsample() is from the Statistics and Machine Learning Toolbox
Piyush Kant
2022-2-7
Is there any method/parameter with which we can reproduce same random series so that the different algorithms can be evaluated? I know that way it wont be a random series anymore still the psudorandomness can be helpful for multiple runs.
Steven Lord
2022-2-7
Some older functions that use random numbers internally (like eigs, which generates a starting point at random if one is not given to it) have the ability to specify inputs that avoid the randomness (in the case of eigs by specifying v0 in the options structure or specifying the StartVector name-value pair argument.)
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