Use of for loop for multiple columns

Hi everyone,

May someone help me.

The code presneted here is work well. I need to modified this for n number of columns (a=s(:,1) is the first column of S). s file consists of 1000 columns.

[Rafael Hernandez-Walls]

[Bruno Luong]

[aa]

hi i am new .. try to apply but failed

[Peter O]

Rafael's suggestions put you on the right track, and he's given you the generalized code for k columns. If I can suggest a slight correction to the array access so that all of the columns are extracted an operated on:

clear all
clc
n_cols = 1000;
s = importdata('data.xlsx');
a=s(:,n_cols);
s_ev = sum(a(1:24,:)); % A slight correction here to extract all columns to pass to the sum function.

% This applies the zero to 0.25 substitution across columns
s_ev(s_ev == 0) = 0.25;
r = s_ev/24;

t = a(25:48,:);

% Taking a guess here that your intent is to divide the next 24 rows by the average for the first 24 rows, for every column.
% This takes advantage of some of MATLAB's broadcast operations to eliminate the for loop.
b = t - r./sqrt(r);

% Gives you the max for each column
c = max(b)

Answer 1

[VBBV]

Try this way

 % If true
    % code
 % end
clear all
clc
s = importdata('data.xlsx');
[R,C] = size(s)
for j = 1:C
  a=s(:,j);
end
  s_ev = sum(a(1:24,:));
 % A slight correction here to extract all columns to pass to the sum function.
%This applies the zero to 0.25 substitution across columns
s_ev(s_ev == 0) = 0.25;
r = s_ev/24;
t = a(25:48,:);
% Taking a guess here that your intent is to divide the next 24 rows by the average for the first 24 rows, for every column.
% This takes advantage of some of MATLAB's broadcast operations to eliminate the for loop.
b = t - r./sqrt(r);
%Gives you the max for each column
c = max(b)

Make sure that you have only numeric data in .xls file of importdata function