How to avoid Warning when assigning values to a table

Question

Louise Wilson 2021-3-25

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/783856-how-to-avoid-warning-when-assigning-values-to-a-table

评论： Louise Wilson 2021-3-25

采纳的回答： Cris LaPierre

wavTimes.mat

在 MATLAB Online 中打开

Hello,

I have the attached table. I create an empty table and then add each variable separately from the name of files in a folder, and then assign them one by one for each row. This works, but I get a warning:

'Warning: The assignment added rows to the table, but did not assign values to all of the table's existing variables. Those variables are extended with rows containing default values. '

So even though there are no problems, I would like to do it in the most robust way. How can I avoid the warning? Is there a way to assign all variables at once for each row?

wavTimes.(rec_SN)=[]; %create empty output table
wavTimes.(rec_SN)=array2table(wavTimes.(rec_SN));
        
%get start and end time of each .wav file in folder
for ii=1:length(d)
    
    disp(d(ii).name);
    filename=fullfile(rec, d(ii).name);
    
    split_fn=strsplit(filename,'.');
    wav_date=datetime(split_fn{2},'InputFormat','yyMMddHHmmss');
    wavTimes.(rec_SN).wavFileName(ii)={d(ii).name};
    wavTimes.(rec_SN).wavDateTime(ii)=wav_date;
    
    wavinfo=audioinfo(filename);
    wav_length=wavinfo.Duration;
    wavTimes.(rec_SN).wavEnd(ii)=wav_date+seconds(wav_length);
end

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Answer 1

Cris LaPierre 2021-3-25

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https://ww2.mathworks.cn/matlabcentral/answers/783856-how-to-avoid-warning-when-assigning-values-to-a-table#answer_658541

编辑：Cris LaPierre 2021-3-25

在 MATLAB Online 中打开

The warning is because you are adding the values to a table one by one. When you add the first value in a new row, all columns are assigned a value. The warning is just that, a warning to let you know values were added to the other variables.

Consider rearranging your setup slightly.

%get start and end time of each .wav file in folder
for ii=1:length(d)
    
    disp(d(ii).name);
    filename=fullfile(rec, d(ii).name);
    
    split_fn=strsplit(filename,'.');
    wav_date=datetime(split_fn{2},'InputFormat','yyMMddHHmmss');
    wavFileName(ii)={d(ii).name};
    wavDateTime(ii)=wav_date;
    
    wavinfo=audioinfo(filename);
    wav_length=wavinfo.Duration;
    wavEnd(ii)=wav_date+seconds(wav_length);
end
wavTimes.(rec_SN) = table(wavFileName,wavDateTime,wavEnd);