Error using length, Too many input arguments.

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C A 2021-8-30

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1443614-error-using-length-too-many-input-arguments

评论： Walter Roberson 2021-9-1

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.

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Answer 1

Matt J 2021-8-30

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https://ww2.mathworks.cn/matlabcentral/answers/1443614-error-using-length-too-many-input-arguments#answer_777419

编辑：Matt J 2021-8-30

The first line shouldn't have any commas.

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Matt J 2021-8-31

在 MATLAB Online 中打开

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 2021-8-31

Thank you. This helps a lot!

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Answer 2

Stephen23 2021-8-31

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1443614-error-using-length-too-many-input-arguments#answer_777934

编辑：Stephen23 2021-8-31

在 MATLAB Online 中打开

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.

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C A 2021-8-31

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 2021-9-1

"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.

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