Merge tables with different dimensions?

Question

Chelsea 2015-2-19

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/179290-merge-tables-with-different-dimensions

评论： Utsav Dave 2023-10-19

采纳的回答： Guillaume

在 MATLAB Online 中打开

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.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Guillaume 2015-2-19

6
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/179290-merge-tables-with-different-dimensions#answer_168601

在 MATLAB Online 中打开

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 个评论
显示 4更早的评论隐藏 4更早的评论

Ayana Cameron 2020-4-10

How would this change to horizontally concatenate?

Marguerite Kennish 2020-8-21

I would like to repeat Ayana Cameron's question:

"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.

请先登录，再进行评论。

Answer 2

Sterling Baird 2020-9-5

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/179290-merge-tables-with-different-dimensions#answer_490207

编辑：Sterling Baird 2020-9-5

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 个评论
显示 -1更早的评论隐藏 -1更早的评论

Utsav Dave 2023-10-19

Awesome! Saved me so much time, thanks Sterling!

请先登录，再进行评论。

Answer 3

Evan 2015-2-19

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/179290-merge-tables-with-different-dimensions#answer_168597

编辑：Evan 2015-2-19

在 MATLAB Online 中打开

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.