Convert spreadsheet that contains variable names and numbers into simple variables

Question

TimonD 2018-11-22

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评论： TimonD 2018-11-29

Hello everyone,

I've been trying to convert a Excel Spreadsheet to variables. The Spreadsheet only has two columns and looks somewhat like this:

Cw     0.35
A        2.7
ig1      4.171  
ig2      2.34  
ig3      1.521
...

as you can see the variable names are written in the first coulmn and the the variable values in the second coulmn.

All i want to do is to extract those variables with the given name and value to my workspace (as a 1x1 table) since I need them that way for my Simulink model. I've tried xlsread and readtable as well as the import data button but i cant get it to output anything different than a table.

There must be a very simple solution to this problem?

Any help would be greatly appreciated. Thank you.

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Stephen23 2018-11-22

You could easily use that .xlsx file to define a structure with those fields. Then within Simulink refer to that structure and its fields.

Magically creating/accessing variable names is not recommended:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

TimonD 2018-11-22

在 MATLAB Online 中打开

Ok Thank you. That really does make sense. I'm still struggeling to define a structure which sets the variable names to the field names tho... I've been browsing the the Matlab help and the forums but i'm still not sure how to dynamicly create the field names with my given spreadsheet. This is all i get:

i guess what i want is a 1x1 structure with 23 fields... i just don't know how to creat it. This is my code so far:

filename=FahrzeugDaten.xlsx
%% Setup the Import Options
opts = spreadsheetImportOptions("NumVariables", 2);
% Specify sheet and range
opts.Sheet = "Daten";
opts.DataRange = "B3:C100";
% Specify column names and types
%opts.VariableNames = ["Variable", "Werte"];
%opts.VariableTypes = ["string", "double"];
opts = setvaropts(opts, 1, "WhitespaceRule", "preserve");
opts = setvaropts(opts, 1, "EmptyFieldRule", "auto");
% Setup rules for import
opts.ImportErrorRule = "omitrow";
opts.MissingRule = "omitrow";
opts = setvaropts(opts, 2, "TreatAsMissing", '');
FahrzeugDaten = table2struct(readtable(filename, opts, "UseExcel", false));

Do you have any ideas on how to do this? Could you point me in the right direction?

P.S. I'm using readtable instead of XLS read becaus i need the missing row feature....

Thank you so much

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Answer 1

dpb 2018-11-22

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/431418-convert-spreadsheet-that-contains-variable-names-and-numbers-into-simple-variables#answer_348442

编辑：dpb 2018-11-22

在 MATLAB Online 中打开

OK, given the example data from the original question in an .xls file -- to build a struct with those variables as fields with the associated values:

>> [v,n]=xlsread('timon.xls');       % values double array, text names cellstr
>> s=cell2struct(num2cell(v),n,1)    % convert to struct w/ field names with values
s = 
  struct with fields:
     Cw: 0.3500
      A: 2.7000
    ig1: 4.1710
    ig2: 2.3400
    ig3: 1.5210
>> 

Or, you can use the raw data returned as cell array--

[~,~,r]=xlsread('timon.xls');
s=cell2struct(r(:,2),r(:,1),1);

will return the same struct

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dpb 2018-11-26

:) I agree! The syntax for building a structure isn't always greatly explained from struct documentation; you have to know the helper functions exist (which means must follow the links of "See Also" to learn about them.

TimonD 2018-11-29