table with NaNs into separate cells

2024 4 24
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I have a table (M) with 4 columns (columns named X, Y, Z,K) , there is a break between the data that loads as NaN.
I want place each data chunk into cells with all 4 columns (X, Y, Z,K).
Thank you!

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Voss
Voss 2024-4-24
Ran in:

2 个投票

Ran in:
% making a table with some all-NaN rows:
Var = randi(100,12,4);
Var([3 9],:) = NaN;
M = array2table(Var)
M = 12x4 table
Var1 Var2 Var3 Var4 ____ ____ ____ ____ 7 12 6 2 80 39 44 44 NaN NaN NaN NaN 48 78 45 83 3 97 37 62 35 55 21 4 37 44 22 79 85 95 92 85 NaN NaN NaN NaN 98 21 58 64 13 57 8 58 96 89 36 89
% split the table on the all-NaN rows into a cell array of tables:
idx = find(all(isnan(M{:,:}),2));
s_idx = [1; idx+1];
e_idx = [idx-1; size(M,1)];
result = arrayfun(@(s,e)M(s:e,:),s_idx,e_idx,'UniformOutput',false)
result = 3x1 cell array
{2x4 table} {5x4 table} {3x4 table}
celldisp(result)
result{1} = Var1 Var2 Var3 Var4 ____ ____ ____ ____ 7 12 6 2 80 39 44 44 result{2} = Var1 Var2 Var3 Var4 ____ ____ ____ ____ 48 78 45 83 3 97 37 62 35 55 21 4 37 44 22 79 85 95 92 85 result{3} = Var1 Var2 Var3 Var4 ____ ____ ____ ____ 98 21 58 64 13 57 8 58 96 89 36 89

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puccapearl
puccapearl 2024-4-24
Thank you Voss, I now have a cell with tables. How can I pull each table that contains a specific column value. For example in the picture above, I want to pull all the tables where the 3rd column == 1 into a separate cell.
I tried but the tables combine as a double which I don't want, I want to keep the separate tables.
Can also repost as a different question.
Voss
Voss 2024-4-24
You're welcome!
One way to have all the tables in separate cells, but only the rows where column 3 is 1, is to split them first, as in my answer, and then:
result = cellfun(@(t)t(t{:,3} == 1,:),result,'UniformOutput',false);
puccapearl
puccapearl 2024-4-24
amazing, thank you!
Voss
Voss 2024-4-25
You're welcome!
puccapearl
puccapearl 2024-4-25
Voss, one more thing, I want to subtract the first and last values of each table in column 1,
I tried this,
F = @(x)x(end)-x(1);
b = cellfun(F, result , 'un',0);
but I need to index into the first column of each table and I'm not sure how to do this.
Voss
Voss 2024-4-25 
F = @(x)x{end,1}-x{1,1};
b = cellfun(F, result);
puccapearl
puccapearl 2024-4-25
编辑：puccapearl 2024-4-25
ah yes I thought so! My issue is, when I do this:
result = cellfun(@(t)t(t{:,3} == 1,:),result,'UniformOutput',false);
I get a cell with some empty tables,
and that gives me an indexing error error when I try to do:
F = @(x)x{end,1}-x{1,1};
b = cellfun(F, result);
Do you know how I can remove the empty tables prior to avoid the error? I tried:
result = table2cell(rmmissing(cell2table(result)))
and
result(cellfun(@isempty,result))=[];
and
result(:,all(ismissing(result)))=[];
and
new_result = rmmissing(result);
but they do not remove the empty tables :/
Voss
Voss 2024-4-25
This is how to do it. Try it again.
result(cellfun(@isempty,result)) = [];
puccapearl
puccapearl 2024-4-25
It works! Thank you Voss! :D
Voss
Voss 2024-4-25
You're welcome!

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