Merge tables with different dimensions?
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Chelsea
el 19 de Feb. de 2015
Comentada: Utsav Dave
el 19 de Oct. de 2023
Hi,
I'm trying to use vertcat to add together a sequence of tables. The problem is, some are 24x22, some are 24x19, etc.
Matlab returns the error
Error using table/vertcat (line 56)
All tables in the bracketed expression must have the same number
of variables.
Is there a way to work around this? Like, adding empty columns?
Thanks so much.
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Respuesta aceptada
Guillaume
el 19 de Feb. de 2015
tables like matrices must have the same number of columns (variables with regards to tables) to concatenate them vertically. In addition, for tables, the variable names must be identical.
You can of course add variables to either table until all the variable names match:
t1 = array2table(magic(5), 'VariableNames', {'a', 'k', 'o', 'p', 'w'});
t2 = array2table(magic(6), 'VariableNames', {'a', 'p', 'o', 'v', 's', 'k'});
t1colmissing = setdiff(t2.Properties.VariableNames, t1.Properties.VariableNames);
t2colmissing = setdiff(t1.Properties.VariableNames, t2.Properties.VariableNames);
t1 = [t1 array2table(nan(height(t1), numel(t1colmissing)), 'VariableNames', t1colmissing)];
t2 = [t2 array2table(nan(height(t2), numel(t2colmissing)), 'VariableNames', t2colmissing)];
t = [t1; t2]
6 comentarios
Marguerite Kennish
el 21 de Ag. de 2020
"How would this change to horizontally concatenate?"
I am trying to build a table by adding a column each iteration of a loop, but the rows of each column has different rows.
Más respuestas (2)
Sterling Baird
el 5 de Sept. de 2020
Editada: Sterling Baird
el 5 de Sept. de 2020
I built on Guillaume's answer a while back, and recently ended up making and submitting a FEX function (tblvertcat) that supports cells in addition to other types which are supported by "missing" (double, char, etc.).
EDIT: I revamped the code to use outerjoin()
1 comentario
Evan
el 19 de Feb. de 2015
Editada: Evan
el 19 de Feb. de 2015
Does this example do what you need?
A = randi(9,4,3)
B = randi(9,4,5)
C = randi(9,4,2)
D(1:4,1:size(A,2)) = A;
D(5:8,1:size(B,2)) = B;
D(9:12,1:size(C,2)) = C
You could then assign individual columns to new arrays which could be used as arguments to the table function. This would give you your zero padding for mismatched rows.
Note that if you are using the table function as sending in your arrays in the fashion
table(A,B,C)
you shouldn't receive errors so long as your variables all have an equal number of rows. It sounds like this isn't what you're doing, but without knowing exactly the way you want to arrange your data via some sample code, it's hard to say more.
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