Extract data with a loop cycle from structure

Question

Stefano Alberti 2020-6-7

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/544070-extract-data-with-a-loop-cycle-from-structure

评论： Ameer Hamza 2020-6-8

采纳的回答： Ameer Hamza

在 MATLAB Online 中打开

Hi,

I need to extract data from structure iteratively as multiple tables.

The response with this code is: 'Unable to use a value of type cell as an index.'

Furthemore I'd like to plot the extracted data.

Many thanks,

Code:

directory = '/Users/Dati/';
S = dir(fullfile(directory,'*.csv')); 
for k = 1:numel(S)
    F = fullfile(directory,S(k).name);
    S(k).data = readtable(F, 'PreserveVariableNames', true, 'ReadVariableNames', true);
end
for i = 1: numel(S)
out(i) = S({i}).data;
end 

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Answer 1

Ameer Hamza 2020-6-8

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/544070-extract-data-with-a-loop-cycle-from-structure#answer_447797

编辑：Ameer Hamza 2020-6-8

在 MATLAB Online 中打开

The correct syntax is

directory = '/Users/Dati/';
S = dir(fullfile(directory,'*.csv')); 
for k = 1:numel(S)
    F = fullfile(directory,S(k).name);
    S(k).data = readtable(F, 'PreserveVariableNames', true, 'ReadVariableNames', true);
end
out = cell(1, numel(S))
for i = 1: numel(S)
out{i} = S(i).data;
end

You need to store the tables in a cell array.

Also, second for-loop is not needed. Following is equivalent

directory = '/Users/Dati/';
S = dir(fullfile(directory,'*.csv')); 
for k = 1:numel(S)
    F = fullfile(directory,S(k).name);
    S(k).data = readtable(F, 'PreserveVariableNames', true, 'ReadVariableNames', true);
end
out = {S.data};

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Stefano Alberti 2020-6-8

编辑：Stefano Alberti 2020-6-8

S.mat

Thanks again Ameer!

I'd like to extract data from the structure, with a dedicated table for each table inside structure.

After that for each column of each table I'd like to apply movmean.

Maybe it is not a good approach 'extract' data but directly apply the movmean to each column inside the structure.

Hope to be clear,

Thanks again.

Ameer Hamza 2020-6-8

The data in the tables are not in numeric format. It is the form of character arrays. Also, there are several columns with text data. How do you decide which column do you want to apply movmean().

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