tables remove one field

I have three fields in a table

T.Position= 'No' '10' '20'
T.Velocity= 'No' '10' '60'
T.Acceleration= 'No' 'No' 'No'

then I want to eliminate the field that have all values 'No' which is only Acceleration

How I can do it??

Thanks

Answer 1

[Chibuzo Nnonyelu]

Goes through each column and deletes a column if the number of 'No' found in the column is equal to the height of the table.

for m = 1:width(T)
   if length(strfind(strjoin(table2cell(T(:, m))), 'No') ) == height(T)
%       delete the column;
        T(:, m) = [];
   end
end

[Jan]

Or:

if all(strcmp('No', table2cell(T(:, m))))

I cannot try this currently, but would this work also:

if all(strcmp('No', T{:, m}))

Answer 2

[Patrick Brown]

It does not work well because you have this error Variable index exceeds table dimensions.

maybe because you are changing the width of T when you delete columns

Answer 3

[Peter Perkins]

I'll assume that your table looks like this:

>> t = table({'No'; 10; 20}, {'No'; 10; 60}, {'No'; 'No'; 'No'}, 'VariableNames',{'Position' 'Velocity' 'Acceleration'})
t =
    Position    Velocity    Acceleration
    ________    ________    ____________
    'No'        'No'        'No'        
    [10]        [10]        'No'        
    [20]        [60]        'No'

(which is not at all clear). How would you do this with any MATLAB array? The answer is essentially the same: loop over the variables in the table, deleting the ones that are all No's, and loop backwards so you're not deleting things out from under yourself. "dot-parens-index" dubscripting makes this almost identical to what you'd do for a double array.

for j = width(t):-1:1
    if all(strcmp(t.(j),'No'))
        t.(j) = [];
    end
end

Another way is to use varfun to figure out what to delete, and then delete all at once.

toDeleteFun = @(x) all(strcmp(x,'No'));
toDelete = varfun(toDeleteFun,t,'OutputFormat','uniform')
t(:,toDelete) = [];

The terminology for tables is "variables", not "fields" or "columns".