How to extract sequences from a table?

Question

James McBrearty 2023-8-22

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2011442-how-to-extract-sequences-from-a-table

评论： James McBrearty 2023-8-22

Hi All,

I am adapting the example by Mathworks, Sequence Classification using Deep Learning,, to work with my own problem.

I have the raw data coming in as a table, and I'm wondering is there a way to split this up into sequences, based on the values in one column, rather than an arbitrary number of rows down?

My table looks like this:

What I would like to do is to convert this to a cellarray, of various double arrays (from this picture above it will be x cells each with 2*y double arrays, however, the real table has a few more columns, so it's just an extension of this).

Many thanks,

James

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the cyclist 2023-8-22

Can you upload the data, or a small representative sample? You can use the paper clip icon in the INSERT section of the toolbar.

James McBrearty 2023-8-22

FCTable.mat

So, FCTable is attached.

What I would like is a cell array, where each cell element corresponds to a specific date (I don't need the date), and the contents of each cell would be the double array for each date.

Thanks

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Answer 1

Matt J 2023-8-22

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https://ww2.mathworks.cn/matlabcentral/answers/2011442-how-to-extract-sequences-from-a-table#answer_1291462

编辑：Matt J 2023-8-22

在 MATLAB Online 中打开

Calling your table T,

out = splitapply(@(x){x} , T{:,[1:10,12:end]},findgroups(T.tradeDate))

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Dyuman Joshi 2023-8-22

"Was there something wrong with the format of the dates?"

The format hid additional information of the datetime values.

The dates might look identical, but the values for hour, minute and seconds were different for the same day. You can check that by using hms.

So, to make the data uniform, all the dates have been shifted to the start of the respective days i.e. 00:00:00

James McBrearty 2023-8-22

Thanks for this - I did convert the dateformat to 'dd/mm/uuuu', and I was hoping that would change them all to be uniform. At least now I know how to use dateshift in the future. Again, thanks so much.

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Answer 2

Matt J 2023-8-22

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2011442-how-to-extract-sequences-from-a-table#answer_1291487

编辑：Matt J 2023-8-22

在 MATLAB Online 中打开

FCTable.mat

Another option, using varfun:

load FCTable
T=FCTable;
T.tradeDate=dateshift(FCTable.tradeDate,'start','day') ;
out = varfun(@(x) x,  T,'Grouping', 'tradeDate','Output','cell')
out = 51×2 cell array
    {46×1 double}    {46×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}
    {48×1 double}    {48×1 double}