Creating a vector using conditions and a cell.

This is what I have in the workspace. I have 3 acceleration vectors (one column each): Ax (799x1 double), Ay(799x1 double) and Az(799x1 double). Also I have a cell called activities: activities (1x4 cell) with this code:

Activities={'Walking','Sitting','Standing','Laying'};

Walking=1;

Sitting=2;

Standing=3;

Laying=4;

What I want to do is to create another vector called "actid"(799x1 double) using this conditions:

if Ay>10

actid=1; %Walking

elseif Ay>5 & Ay<7.5

actid=2; %Sitting

elseif Ay<10 & Ay>9

actid=3; %Standing

elseif Ay<1 & Az>9

actid=4; %Laying

end

Running this code I can't get what I want.

I don't know if it is possible to do.

Thank you.

[Stephen23]

Your example code refers to Ay six times, Az one time, and Ax zero times. Is that intentional?

In any case, the solution will be to operate on the entire vectors as once (and not use IFs or similar constructs).

[Julen Aramendi]

First of all, thanks for answering me.

Yeah, it is intentional. Yesterday I didn't explain very well what I want. What I want is that depending the values of the acceleration in X(Ax), Y(Ay) and Z(Az) axles, know if the person is walking, sitting, standing or laying. For that reason, in that case I don't need the acceleration in the axis X because with the other two acceleration axis (Y and Z) is enough.

I don't understand what you want to say with "operate on the entire vectors". Can you give me a simple example?

Thank you.

[Stephen23]

"operate on the entire vectors". Can you give me a simple example?"

Simon Chan's answer is an example. Indexing would be another vectorized approach. See:

https://www.mathworks.com/help/matlab/matlab_prog/vectorization.html

The difference is thinking in terms of matrices/arrays, not individual elements.

Answer 1

[Simon Chan]

Try this:

Zeros in the matrix means all conditions are not meet

actid=(Ay>10) + (Ay>5 & Ay<7.5)*2 + (Ay<10 & Ay>9)*3 + (Ay<1 & Az>9)*4