function with text string input and excel file

Question

ML 2022-5-19

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1723030-function-with-text-string-input-and-excel-file

评论： Voss 2022-5-19

Cars.xlsx

How can I write a function that takes input of (filename, user_input)... basically the user input would be a text string that will return the values of the corresponding string from the excel sheet.

ex: i want to get info from car model x so my input is 'x' then it returns the following:

car model color HorsePower Mileage

x red 250 20

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Answer 1

Voss 2022-5-19

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1723030-function-with-text-string-input-and-excel-file#answer_967435

在 MATLAB Online 中打开

Cars.xlsx

warning off all
get_car_info('Cars.xlsx','x')
ans = 1×4 table
    carModel     color     HorsePower    Mileage
    ________    _______    __________    _______

     {'x'}      {'red'}       250          20   
get_car_info('Cars.xlsx','y')
ans = 1×4 table
    carModel     color      HorsePower    Mileage
    ________    ________    __________    _______

     {'y'}      {'blue'}       350          27   
get_car_info('Cars.xlsx','z')
ans = 1×4 table
    carModel      color      HorsePower    Mileage
    ________    _________    __________    _______

     {'z'}      {'green'}       200          36   
function out = get_car_info(filename,model)
T = readtable(filename);
% two ways, depending on what the input files might look like:
% 1) this finds where the user-input "model" is located in the first 
%    column of the table, which may or may not be called "carModel":
out = T(strcmp(T{:,1},model),:);
% 2) this finds where the user-input "model" is located in "carModel"
%    column of the table, which may or may not be the first column:
out = T(strcmp(T.carModel,model),:);
end

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ML 2022-5-19

Thanks thats reallly helpful. What I meant to aask is what if my input is 'z' but its not there how could I get an error for that?

Voss 2022-5-19

在 MATLAB Online 中打开

Including an error check for unmatched specified model:

function out = get_car_info(filename,model)
if ~nargin
    error('not enough input arguments'); % error if no inputs
elseif nargin < 2
    model = 'x'; % default model value if only one input
end
T = readtable(filename);
% two ways, depending on what the input files might look like:
% 1) this finds where the user-input "model" is located in the first 
%    column of the table, which may or may not be called "carModel":
idx = strcmp(T{:,1},model);
% 2) this finds where the user-input "model" is located in "carModel"
%    column of the table, which may or may not be the first column:
idx = strcmp(T.carModel,model);
% in either case, check that there is a valid model match:
if ~any(idx)
    error('model %s does not appear in the table',model);
end
% return the sub-table matching model:
out = T(idx,:);
end