Select columns of a table using matching column names

Question

Enrico Gambini 2022-6-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1740375-select-columns-of-a-table-using-matching-column-names

评论： Voss 2022-6-15

Hello everyone!

I'm facing the following problem: I have a cell array containing strings, let's call it "v"

On the other hand I have a huge table , let's call it "T", from which I want to select only the columns that have the column name that corresponds to the names contained in vector "v".

Any kind of help will be appreciated

Thank you

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

Voss 2022-6-14

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1740375-select-columns-of-a-table-using-matching-column-names#answer_985640

在 MATLAB Online 中打开

v = {'Var1' 'Var3'}
v = 1×2 cell array
    {'Var1'}    {'Var3'}
T = table([1;2;3],[4;5;6],[7;8;9])
T = 3×3 table
    Var1    Var2    Var3
    ____    ____    ____

     1       4       7  
     2       5       8  
     3       6       9  
% a table of the selected columns of T:
new_T = T(:,v)
new_T = 3×2 table
    Var1    Var3
    ____    ____

     1       7  
     2       8  
     3       9  
% or, the data from the selected columns of T:
new_T_data = T{:,v}
new_T_data = 3×2
     1     7
     2     8
     3     9

2 个评论
显示无隐藏无

Enrico Gambini 2022-6-15

It worked, thank you! And what if not all the elements in v are present as column names in T?

Voss 2022-6-15

在 MATLAB Online 中打开

If not all elements of v are column names of T, you can use ismember to get just the elements of v that do correspond to column names of T:

v = {'Var1' 'Var3' 'Var4'}
v = 1×3 cell array
    {'Var1'}    {'Var3'}    {'Var4'}
T = table([1;2;3],[4;5;6],[7;8;9])
T = 3×3 table
    Var1    Var2    Var3
    ____    ____    ____

     1       4       7  
     2       5       8  
     3       6       9  
v_to_use = v(ismember(v,T.Properties.VariableNames))
v_to_use = 1×2 cell array
    {'Var1'}    {'Var3'}

And use that the same as v was used before:

new_T = T(:,v_to_use)
new_T = 3×2 table
    Var1    Var3
    ____    ____

     1       7  
     2       8  
     3       9  
new_T_data = T{:,v_to_use}
new_T_data = 3×2
     1     7
     2     8
     3     9