Convert table and obtain column values

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Collegue 2019-9-13

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回答： Steven Lord 2019-9-18

Hello, I have this table

How can I first generate an array of string and numbers and then replace the '---' with NaN. Finally I would need to get the values of the Var4 and Var 7.

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KALYAN ACHARJYA 2019-9-13

Have you check here readtable?

Collegue 2019-9-13

Yes I have conberted to table and that is the table that i have obtained.

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Answer 1

Jalaj Gambhir 2019-9-16

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在 MATLAB Online 中打开

Hi,

For the particular task one possible solution could be by first converting the table to cell array using table2cell. And then traversing through the structure to search for ‘- -’ and replacing it with ‘NaN’

T = cell(CellArray); 
for i=1:length(CellArray) 
    for j= 1:length(CellArray{1}) 
        if ~isequal(CellArray{i,j},'--') 
            T{i,j} = CellArray{i,j}; 
        else 
            T{i,j} = NaN; 
        end 
    end 
end 
R = cell2table(T); 

And finally access the 4th and 7th column from the table by:

R(:,[4,7])

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Collegue 2019-9-18

Thank you very much1!! it works!!

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Answer 2

Steven Lord 2019-9-18

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Use ismissing to locate the missing values (you can tell ismissing what it should consider as a missing value) then use the logical array output to replace the missing values with whatever value you want.

The fact that you're changing the data type (potentially for some but not all of the values of a table variable) could complicate things a bit, but if that's the case show a larger sample of your table (maybe two or three rows that have a missing value and two or three that don't) and we may be able to help you determine how to handle that situation.