MATLAB: How to change data type of table in matlab

exceltable

I am reading a spreadsheet with 2 columns using readtable command in Matlab. Both columns of the table are read as a string. How two change the datatype of a second column to double.

Best Answer

Really, you should change the way you store your data in the spreadsheet. As it is you're losing most of the benefit of the spreadsheet format. Even in excel, you wouldn't be able to use those numbers as they're stored as text.

One of the many ways of extracting the numbers from the text:

t = readtable('book1.xlsx');
t.patient = cellfun(@str2double, regexp(t.patient, '\d+', 'match'), 'UniformOutput', false)

If you didn't have those brackets [] around the text and the numbers had beens separated by spaces, it would have been easier.

Related Solutions

MATLAB: How to use the excel import functionality in Matlab to import a table but to have the individual pices of data in the table rows to not be imported as 1×1 tables as well

I imagine what's happening is this: you are importing a spreadsheet using readtable, and you get a table.

>> t = readtable('myfile.xlsx')
t =
  5×3 table
     Var1       Var2       Var3  
    _______    _______    _______
    0.81472    0.09754    0.15761
    0.90579     0.2785    0.97059
    0.12699    0.54688    0.95717
    0.91338    0.95751    0.48538
    0.63236    0.96489    0.80028

Then you select one element of that table:

>> t(1,1)
ans =
  table
     Var1  
    _______
    0.81472

And so you are thinking that the import has created a bunch of little 1x1 tables.

But that isn't it at all. The short answer is that you likely need to use some other form of subscripting, probably something like

>> t.Var1(1)
ans =
      0.81472

The longer answer is that you likely do not want to select one value at a time. Doing vectorized calculations is usually the better way. No way to tell without more context.

There's a whole doc section of how to use subscripting to access data in a table.

MATLAB: Read spreadsheet, delete some variables, and save the spreadsheet

Something like this

t = readtable('test.csv');
t.number_of_deadlines = [];
writetable(t, 'test2.csv')

Best Answer

Related Solutions

MATLAB: How to use the excel import functionality in Matlab to import a table but to have the individual pices of data in the table rows to not be imported as 1×1 tables as well

MATLAB: Read spreadsheet, delete some variables, and save the spreadsheet

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