How do I convert a column of struct array to split into multiple columns in a table

Question

Andrew Feenan 2022-9-1

0
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https://ww2.mathworks.cn/matlabcentral/answers/1793190-how-do-i-convert-a-column-of-struct-array-to-split-into-multiple-columns-in-a-table

评论： Andrew Feenan 2022-9-7

Hi,

I have a struct array and when I use struct2table to convert it to a table some of the data appears as 1x2 double or 2x2 double (see below).

I want to combine the name column and one other data column into a table.

I have tried this

for i = 1:18
    C(i).Name = data3(i).Name;
    C(i).TestData = data3(i).TestData;
end
Table4 = struct2table(C);

The name column is fine, but the confidence interval one displays as

>> disp(Table4)
    TestData
    ____________
    {2×3 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×1 double}
    {2×3 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×2 double}
    {2×1 double}

Is there a way to split the double up so that each array displays in a column in the table, for example:

Name Test Data1 TestData2 TestData3

2 个评论
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Stephen23 2022-9-7

How does a 2x3 matrix correspond to the four columns of the table?

How does a 2x2 matrix correspond to the four columns of the table?

How does a 2x1 matrix correspond to the four columns of the table?

Andrew Feenan 2022-9-7

What do you mean?

The names go in the name column, if it's a 2x3 matrix it should fill all 3 Test Data columns, if it's a 2x2 matrix it should fill the first 2 Test Data columns etc.

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Answer 1

Geetla Sindhu 2022-9-7

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1793190-how-do-i-convert-a-column-of-struct-array-to-split-into-multiple-columns-in-a-table#answer_1045035

在 MATLAB Online 中打开

You can try the following steps:

% Convert your cell arrays in TestData into arrays using cell2mat
t1 = varfun(@cell2mat, Table4, 'InputVariables', {'TestData'});
t1.Properties.VariableNames = {'TestData'};  
% varfun modifies the names, change them back
% Split TestData into multiple columns
t1 = splitvars(t1, 'TestData', 'NewVariableNames', {'TestData1', 'TestData2', 'TestData3'});
% Finally expand Name column
t1.Name = repelem(Table4.Name, [3,2,1]);

You can look at the following example for better understanding:

T = 3×2 table
data            Name
{3×3 double}    "Chang"
{2×3 double}    "Brown"
{[79 75 74]}    "Ruiz"

>>t1 = varfun(@cell2mat, T, 'InputVariables',{'data'});
>>t1.Properties.VariableNames = {'data'};
>>t1 = splitvars(t1, 'data', 'NewVariableNames', {'data1', 'data2', 'data3'});
>> t1.Name = repelem(T.Name,[3,2,1]);

>> t1
6×4 table
data1    data2    data3     Name     
79       75        73     "Chang"
180      178     177.5    "Chang"
220      210       205    "Chang"
79       75        73     "Brown"
180      178     177.5    "Brown"
79       75        74     "Ruiz"