logical indexing within groups
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I have a panel data set such that N observations occur over t-time periods. I've created a unique id number for each N-observation which repeats over t-time periods. See photo for example.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/166254/image.png)
Next, I'd like to extract all the individuals such that hsClass==5 & hsClass<5.
Normally a table (table name is panel1) indexing could be achieved by
rows = panel1.hsClass==5 & panel1.hsClass<5;
panel2 = panel1(rows,:);
However, this results in a table with zero rows. In my case I want the indexing to be performed over the grouping variable (G). How can this be done?
2 Comments
Andrei Bobrov
on 24 Jul 2017
Edited: Andrei Bobrov
on 24 Jul 2017
Please attach your data as mat file.
Answers (1)
Walter Roberson
on 24 Jul 2017
[uG, ~, Gidx] = unique(panel1.G);
group_has_a_5 = accumarray(Gidx, panel1.hsclass == 5) >= 1;
row_mask = ismember(panel1.G, uG(group_has_a_5) );
panel2 = panel1(row_mask,:);
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