How do we count non-zero entries in every column in a table?

2 views (last 30 days)
Dear experiences
i have a sparse matrix stored in an excel file, i read this matrix using (read table), i need to count every non-zero entries in every column and remove columns that do not satisfy condition (like K where k=3) such that remove columns that involve 1 and 2 non-zero entries and saved others. note: when columns are removed must be removed along with its header or "title" information using Matlab 2015?
thanks for any participation ...

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 30 Mar 2017
Let T - your table:
x = [0 0 193 0 0 0 37 0;
53 0 0 0 0 0 0 0;
0 161 0 0 0 0 0 0;
0 0 47 160 0 0 6 15;
0 186 98 0 0 0 0 0;
0 147 125 53 0 0 34 0;
0 0 0 0 0 0 196 0;
0 0 0 0 0 0 143 164;
0 0 0 0 0 0 101 0;
102 92 0 145 0 0 0 0];
xc = num2cell(x,1);
T = table(xc{:},'VariableNames',cellstr(strcat(string('column_'),string(1:numel(xc)))));
k = 3;
t = varfun(@(x)sum(x~=0),T ,'OutputFormat','uniform');
% or t = sum(T{:,:} ~= 0);
out_table = T(:,t >= k);
  3 Comments
Andrei Bobrov
Andrei Bobrov on 31 Mar 2017
x = readtable('c.xls')
k = 3;
y = x(:,2:end);
t = sum(y{:,:} ~= 0);
out_table = [x(:,1),y(:,t >= k)];

Sign in to comment.

More Answers (0)

Products

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!