For Loop Help Needed

Hey guysss,

So I am trying to write a for loop to automatically detrend my signal until the "constant" value, or 0. I am using an updated detrend function that allows for higher order detrending rather than just linear.

%Detrend

Order.Max = 5;

X = 0:Order.Max - 1;

X = sort(X,'descend');

T1.Prc = detrend(T1.Sig1,Order.Max);

T2.Prc = detrend(T2.Sig1,Order.Max);

T3.Prc = detrend(T3.Sig1,Order.Max);

T4.Prc = detrend(T4.Sig1,Order.Max);

T5.Prc = detrend(T5.Sig1,Order.Max);

for Order.Low = X,

T1.Prc = detrend(T1.Prc,Order.Low);

T2.Prc = detrend(T2.Prc,Order.Low);

T3.Prc = detrend(T3.Prc,Order.Low);

T4.Prc = detrend(T4.Prc,Order.Low);

T5.Prc = detrend(T5.Prc,Order.Low);

end

I keep getting this error: ??? Error: File: fieldanalysisPART1.m Line: 18 Column: 10 Unexpected MATLAB operator.

Can you help me correct this? I essentially want the for loop to detrend the original signal T1.Sig1 with the highest order (for example, Order.Max = 5) and save it to T1.Prc. Then, I want the for loop to detrend T1.Prc with 4,3,2,1, and 0.

Answer 1

[David Young]

It would help if you told us which is line 18, but I'm guessing it's probably the one that says:

for Order.Low = X,

since this will provoke the error message you get.

The reason is that you need to provide a simple variable name for the for-loop. You should try replacing the line above with these two lines:

for x = X
  Order.Low = x;

(omitting also the extraneous comma). There may be other problems, but that will at least deal with the message you're getting now.

As a side point, instead of

X = 0:Order.Max-1;
X = sort(X, 'descend');

you could write

X = Order.Max-1 : -1 : 0;

[Sarah]

That did solve my error, but I don't think it gives me the solution that I want. For example, I essentially want the for loop to be able to do this:

The highest order is 4:

% T1.Prc = detrend(T1.Sig1,4);

% T2.Prc = detrend(T2.Sig1,4);

% T3.Prc = detrend(T3.Sig1,4);

% T4.Prc = detrend(T4.Sig1,4);

% T5.Prc = detrend(T5.Sig1,4);

%

% T1.Prc = detrend(T1.Prc,3);

% T2.Prc = detrend(T2.Prc,3);

% T3.Prc = detrend(T3.Prc,3);

% T4.Prc = detrend(T4.Prc,3);

% T5.Prc = detrend(T5.Prc,3);

%

% T1.Prc = detrend(T1.Prc,2);

% T2.Prc = detrend(T2.Prc,2);

% T3.Prc = detrend(T3.Prc,2);

% T4.Prc = detrend(T4.Prc,2);

% T5.Prc = detrend(T5.Prc,2);

% T1.Prc = detrend(T1.Prc,'linear');

% T2.Prc = detrend(T2.Prc,'linear');

% T3.Prc = detrend(T3.Prc,'linear');

% T4.Prc = detrend(T4.Prc,'linear');

% T5.Prc = detrend(T5.Prc,'linear');

%

% T1.Prc = detrend(T1.Prc,'constant');

% T2.Prc = detrend(T2.Prc,'constant');

% T3.Prc = detrend(T3.Prc,'constant');

% T4.Prc = detrend(T4.Prc,'constant');

% T5.Prc = detrend(T5.Prc,'constant');

^where linear and constant are 1 and 0 respectively