campare a row value with the next row
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Hi
I have the following column:
1
1
0
0
0
1
0
1
0
1
I want to campare rows value one by one with the next row ( first with second, second with third ... and ninth with tenth) and check if it changes for 1 to 0, 0 to 0, 0 to 1 and 1 to 1. For each of these conditions, I want to count them. I tried using loop and diff or sign and equations but I could not work out because the results will be similar for two conditions.
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Accepted Answer
Rik
on 20 Feb 2020
You were close when using diff. You need to think what characterizes all four combinations. The code below should be what you need.
v=[1;1;0;0;0;1;0;1;0;1];
d=diff(v);
u=v(1:(end-1));%shrink by 1 to make it the same size as d
clc
%if [0;0]
%then diff==0, v==0
L= d==0 & u==0;
fprintf('[0 0]: %d\n',sum(L))
%if [0;1]
%then diff==-1
L= d==-1;
fprintf('[0 1]: %d\n',sum(L))
%if [1;0]
%then diff==1
L= d==1;
fprintf('[1 0]: %d\n',sum(L))
%if [1;1]
%then diff==0, v==1
L= d==0 & u==1;
fprintf('[1 1]: %d\n',sum(L))
More Answers (1)
Alex Mcaulley
on 20 Feb 2020
Edited: Alex Mcaulley
on 20 Feb 2020
Another option:
a = [1;1;0;0;0;1;0;1;0;1];
b = diff(a);
b(~b) = 2*a(~b);
sol = splitapply(@numel,b,b+2) %Ordered as [1,0],[0,0],[0,1],[1,1]
sol =
3 2 3 1
4 Comments
Alex Mcaulley
on 21 Feb 2020
With your second column it should work fine, because you have all the possible combinations.
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