random selection of a cell

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KK14
KK14 2020-7-22
编辑： Bruno Luong 2020-7-22
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
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KK14
KK14 2020-7-22
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 2020-7-22
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
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KSSV
KSSV 2020-7-22
编辑：KSSV 2020-7-22
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 2020-7-22
Thankyou for the answer.Idea works just fine.

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Bruno Luong
Bruno Luong 2020-7-22
A = zeros(100,100);
something = 1;
for c = 1:100
r = randi(97) + (0:3);
A(r,c) = something;
end
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Bruno Luong
Bruno Luong 2020-7-22
编辑：Bruno Luong 2020-7-22
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 2020-7-22
Thankyou for the answer.Had to modify, but the idea helped.

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