Error using length, Too many input arguments.

I have a bunch of data from animal cells at different times. j represents the time frame. I want to extract a field from my object and that field can either have one or two values. If I have one value, I want to extract the value as it is and if I have two values, I want to average them out. This is a snippet of my code.

                        if length(Obj.MatFile{cellnumber}{j},ExtractField)==2 
                            Answer(icellnumber,i)=mean(Obj.MatFile{cellnumber}{j}.(ExtractField));
                        else 
                            Answer(icellnumber,i)=Obj.MatFile{cellnumber}{j}.(ExtractField);                        
                        end

I keep getting the above error. Any help would be greatly appreciated. Thanks in advance.

Answer 1

[Matt J]

The first line shouldn't have any commas.

[C A]

With the '.' I get "Reference to non-existent field 'ExtractField'." error because ExtractField is a variable and it is not directly found in the object. Thanks.

[Matt J]

Ina later line of the code, you have

 Obj.MatFile{cellnumber}{j}.(ExtractField)

Shouldn't it be referenced that way everywhere else, too?

[C A]

Thank you. This helps a lot!

Answer 2

[Stephen23]

if length(Obj.MatFile{cellnumber}{j}.(ExtractField))==2

But note that you do not need to check the length: taking the mean of one value simply returns that value, so in both cases you can simply do this (and not worry about how many values there are):

Answer(icellnumber,i) = mean(Obj.MatFile{cellnumber}{j}.(ExtractField));

and then get rid of the IF entirely.

[C A]

Thank you. This is the most sensible way to do this. I just wanted to learn how to use 'length' function because I need to remove values if there are more than two.

[Walter Roberson]

"if there are more than two" -- use numel() instead of length() if you want to know how many values there are. length() has a slightly different meaning.