random selection of a cell

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KK14
KK14 le 22 Juil 2020
Modifié(e) : Bruno Luong le 22 Juil 2020
Hello,
I have a cell(matrix) of size 100*100.I need to scan each column and choose 4 consecutive random cells( (1*1)*4) for assigning values.Can anyone please help me with this?
Thanks in advance
  2 commentaires
madhan ravi
madhan ravi le 22 Juil 2020
A short example?
KK14
KK14 le 22 Juil 2020
I have a 100*100matrix. Suppose I take x as my random value & column say 'y'.So my selection among the 100 elements in the column should be (x:x+4, y)
ex: if x = 7, y =4
selection = (7:10, 4)

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KSSV
KSSV le 22 Juil 2020
You got 100 columns.....you can pick any one element/ position out of it randomly using randperm.
% loop for each column
for i = 1:100
% pick element randomly
p = randperm(100,1) ;
end
  3 commentaires
KSSV
KSSV le 22 Juil 2020
Modifié(e) : KSSV le 22 Juil 2020
You said you want continuously right? Then simply taken next four from them.
% loop for each column
for i = 1:100
% pick element randomly
p = randperm(100,1) ;
if p > 96
p = 96 ;
end
idx = p:p+4 ;
end
KK14
KK14 le 22 Juil 2020
Thankyou for the answer.Idea works just fine.

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Plus de réponses (1)

Bruno Luong
Bruno Luong le 22 Juil 2020
A = zeros(100,100);
something = 1;
for c = 1:100
r = randi(97) + (0:3);
A(r,c) = something;
end
  3 commentaires
Bruno Luong
Bruno Luong le 22 Juil 2020
Modifié(e) : Bruno Luong le 22 Juil 2020
Replace "r = randi(97) ..." by
ncons = 4;
r = randi(size(A,1)-ncons+1)+(0:ncons-1)
You also specify 4 consecutive rows in your original question. Feel free if you want change 4 to something else.
KK14
KK14 le 22 Juil 2020
Thankyou for the answer.Had to modify, but the idea helped.

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