How to split an array into two arrays?
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Hi,
I have an array like x = [ 0:10] and need to split it into x1 = [x(0,1),x(4,5),x(8,9)] and x2 = [x1(2,3),x(6,7)]. I am able to do this by using loops but for big dara is very time consuming. Is there any other way to do this?
Thanks
5 个评论
Sindar
2020-1-20
Do you mean:
A)
x1 = [x(0),x(1),x(4),x(5),x(8),x(9)];
x2 = [x(2),x(3),x(6),x(7)];
B)
x1 = [x(0),x(1) ; x(4),x(5) ; x(8),x(9)];
x2 = [x(2),x(3) ; x(6),x(7)];
(all indexes shifted up by 1 since x(0) isn't correct in Matlab)
C) something else?
This should work for A)
x=0:10;
n = length(x);
inds_1 = [0;1] + (1:4:n-1);
x1 = x(inds_1(:));
inds_2 = [0;1] + (3:4:n-1);
x2 = x(inds_2(:));
B)
x=0:10;
n = length(x);
inds_1 = [0;1] + (1:4:n-1);
x1 = x(inds_1);
inds_2 = [0;1] + (3:4:n-1);
x2 = x(inds_2);
KSSV
2020-1-20
Note that there is no zero index in MATLAB. x(0) throws error.
Your x is an array of dimension 1x11, so using x(4,5) etc., mentioning two indices throws error. What exactly you want to do?
Stephen23
2020-1-20
Mohammad Torabi's "Answer" moved here:
Thanks for your reply, actually I did not represent the question very well, the number of items I need to extract from x is not always 2 and it is a variable and also x is a very big array. In below example, I used 10 instead of 2 for better illustration. Generally, data of x1 and x2 are stored within x alternatively like bellow:
x = [a1,a2,...,a10,b1,b2...,b10,a11,a12,...,a20,b11,b12,...,b20,a21,....]
x1 = [a1,a2,a3,...] include all a values
x2 = [b1,b2,b3,...] include all b values
Stephen23
2020-1-20
First reshape and then use indexing.
Mohammad Torabi
2020-1-20
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