How to select a specific element in a table using variables corresponding to table headers

Question

Rafael Cordero 2021-5-31

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/844325-how-to-select-a-specific-element-in-a-table-using-variables-corresponding-to-table-headers

编辑： Stephen23 2021-5-31

采纳的回答： Stephen23

在 MATLAB Online 中打开

Hello all,

Imagine I have the following table T:

I would like to programatically extract a specific Order corresponding to a specific Reference that is given in a separate variable.

Example, for:

var_name = 'Charlie'

What is the syntax to extract Charlie's Order (i.e. 15) using var_name?

Thank you

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Answer 1

Stephen23 2021-5-31

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/844325-how-to-select-a-specific-element-in-a-table-using-variables-corresponding-to-table-headers#answer_713460

编辑：Stephen23 2021-5-31

在 MATLAB Online 中打开

How to select data from a table is explained here:

https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-table.html

Ref = {'Catherine';'Bob';'Fred';'Anna'};
Order = [15;13;13;4];
Lambda = [12;14;21;46];
% name you want to match:
name = 'Catherine';

By far the easiest way is to use row names:

T1 = table(Order,Lambda,'RowNames',Ref)
T1 = 4×2 table
                 Order    Lambda
                 _____    ______

    Catherine     15        12  
    Bob           13        14  
    Fred          13        21  
    Anna           4        46  
out = T1{name,'Order'}
out = 15

Without row names requires the use of indexing (e.g. via STRCMP or similar):

T2 = table(Ref,Order,Lambda)
T2 = 4×3 table
         Ref         Order    Lambda
    _____________    _____    ______

    {'Catherine'}     15        12  
    {'Bob'      }     13        14  
    {'Fred'     }     13        21  
    {'Anna'     }      4        46  
idx = strcmpi(T2.Ref,name);
out = T2{idx,'Order'}
out = 15