# Array creation with condition from another array

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Sferle Alin-Tudor on 30 May 2021
Commented: Sferle Alin-Tudor on 30 May 2021
Hi,
I have an array like that x and I want to verify if two consecutive elements from it are 00,01,10 or 11, and at these conditions I will initialize in another array a single value like in the code:
x = randi([0,1],1,n);%n is input from a text box
for i=1:2:length(x)%i verify from 2 in 2 values from array
if(x(i)==0 && x(i+1)==0)
y(i)=1;
elseif(x(i)==0 && x(i+1)==1)
y(i)=3;%and so on for 10,11
end
end
The problem is that how can I minimize the size of y array because in this way, the program assigns me 1 for y(0) and for y(1) the value from x(1). I want in a way to delete x(1) in order to remain only values from y(0),y(2),... and so on.

Asmit Singh on 30 May 2021
You can do this by mapping 2 consecutive indices to one index, ie. {1, 2} to 1, {3,4} to 2 and so on.. The following code should help
x = randi([0,1],1,n);%n is input from a text box
for i=1:2:length(x)%i verify from 2 in 2 values from array
%j maps index for y to index for x
j = fix(i/2)+1;
if(x(i)==0 && x(i+1)==0)
y(j)=1;
elseif(x(i)==1 && x(i+1)==0)
y(j)=2;
elseif(x(i)==0 && x(i+1)==1)
y(j)=3;
else
y(j)=4;
end
end
Sferle Alin-Tudor on 30 May 2021
Thanks

R2020b

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