How to convert a table data to numeric data without loosing data

Question

C PRASAD 2022-3-18

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https://ww2.mathworks.cn/matlabcentral/answers/1674494-how-to-convert-a-table-data-to-numeric-data-without-loosing-data

回答： Walter Roberson 2022-3-18

I have a tabel data and I would like convert it to numeric data. I have used table2aray then I get the into String.But I want it as a Numeric data and Then I used str2double and I got the double type data where I lost the sata of 6 column.Now I want to conert my table data into Numeric and No information could not be lost.Please help me with this using MATALAB

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Arif Hoq 2022-3-18

data of column 6 is string, so if you want to convert into numeric it will return 'NaN'. you have to work with this column 6 as a cell array of character vector or a string array.

what is you expectation except this ?

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Answer 1

Walter Roberson 2022-3-18

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https://ww2.mathworks.cn/matlabcentral/answers/1674494-how-to-convert-a-table-data-to-numeric-data-without-loosing-data#answer_920789

在 MATLAB Online 中打开

data = table([1;2], [3;4], [5;6], ["Healthy";"Disease"], 'variablenames', {'Energy', 'variance', 'std', 'class'})
data = 2×4 table
    Energy    variance    std      class  
    ______    ________    ___    _________

      1          3         5     "Healthy"
      2          4         6     "Disease"
[data.class, groups] = findgroups(data.class)
data = 2×4 table
    Energy    variance    std    class
    ______    ________    ___    _____

      1          3         5       2  
      2          4         6       1  
groups = 2×1 string array
    "Disease"
    "Healthy"
table2array(data)
ans = 2×4
     1     3     5     2
     2     4     6     1

That is, the class data has been grouped into categories, and for each entry a category number was generated and replaces the strings in the table. Now the class column is a code that indicates the class, but has no inherent numeric meaning. You can take the value of the column and use it to index the groups variable to recover the class string information.