Looping matrice column by subtraction
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I have a 84x7 matrices. On the entire column 2 and 4, they need to be subtracted from higher number - lower and loop through the whole 84 rows and put them into a new 84x1 vector. How can this be done? let 4x4 matrix a = [x 3 2 y; x 4 1 y; x 1 6 y; x 2 7 y; x 5 1 y;
b= [3-2 4-1 6-1 7-2 5-1]
b= [1 3 5 5 4 ]
1 个评论
madhan ravi
2018-10-21
A small example? And your desired output?
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madhan ravi
2018-10-21
编辑：madhan ravi
2018-10-21
EDIT 2
a = randi([0 9],84,7) %fake data to test
a1=a(:,2) %column you want to extract
a2=a(:,5) %column you want to extract
a=[a1 a2] %two columns stored in a matrix , sorry I missed this line which caused the error
idx = find(a1<a2)
a(idx,:)=fliplr(a(idx,:))
b = a(:,1) - a(:,2) % as column vector
b1 = b' %row vector
12 个评论
madhan ravi
2018-10-21
if it doesn't meet your requirement let know
Young Lee
2018-10-21
madhan ravi
2018-10-21
编辑：madhan ravi
2018-10-21
See edited answer now , no need loop to attain the desired result
Young Lee
2018-10-21
madhan ravi
2018-10-21
It’s like you gave in the example right? Am I missing something?
madhan ravi
2018-10-21
编辑：madhan ravi
2018-10-21
use abs(the_value) to get positive result, if you don’t want to use abs() upload the matrix which you are testing because as you can see it works very well for the example you gave here
madhan ravi
2018-10-21
编辑：madhan ravi
2018-10-21
Can you upload x(:,2) & x(:,5) datas here so that it can be tested
Young Lee
2018-10-21
madhan ravi
2018-10-21
check the edited code now
Young Lee
2018-10-21
madhan ravi
2018-10-21
编辑：madhan ravi
2018-10-21
Anytime:)
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