No need of specifying format(%s) there, MATLAB takes automatically respective data type
data = readtable('Ge single crystal transmission.txt'); % there is empty column(3rd)
data.Var3 = []; % remove 3rd variable because its empty
If you want data as numberic array
data = readmatrix('Ge single crystal transmission.txt'); % numeric array and empty column(3rd)
data(:,3) = []; %remove 3rd column because its nan values(empties)
