# How would I take the mean of each row from column_13 of 79 csv files?

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muhammad choudhry on 17 Jun 2022
Commented: Karim on 17 Jun 2022
Hi,
I am completely stuck here. I am trying to take the mean of each row of column 13 in the 79 csv files and there are 48 rows in total in each file but I am struggling to make a code here. I anyone can help.
Code tried so far:
close all; clear all; clc;
P = 'F:\3-PIV_Experimental_Data\Calculations_TurbulentIntensity\line_Data\Elliptical_Side_LSB\Length\DesignPoint\110_outlet';
S = dir(fullfile(P,'*.csv'));
N = natsortfiles({S.name});
TurbulentFluctuationArray_Mean=zeros(numel(N), 1);
for i = 1:numel(N);
data = readtable( fullfile(P, N{i}) ); % read the csv files
col_13(i) = mean([data(:,13)])
end
Error:
Error using sum
Invalid data type. First argument must be numeric or logical.
Error in mean (line 127)
y = sum(x, dim, flag) ./ mysize(x,dim);
Error in rowMean_practise (line 10)
col_13(i) = mean([data(:,13)],79)
##### 2 CommentsShowHide 1 older comment
muhammad choudhry on 17 Jun 2022
here are 2 of them and I have 79 0f them.

Karim on 17 Jun 2022
Edited: Karim on 17 Jun 2022
You were almost there, you just need to convert the table to an array to take the mean of the values, see below for a quick fix:
P = 'F:\3-PIV_Experimental_Data\Calculations_TurbulentIntensity\line_Data\Elliptical_Side_LSB\Length\DesignPoint\110_outlet';
S = dir(fullfile(P,'*.csv'));
N = natsortfiles({S.name});
TurbulentFluctuationArray_Mean=zeros(numel(N), 1);
col_13_data = zeros(48,numel(N))
for i = 1:numel(N);
data = readtable( fullfile(P, N{i}) ); % read the csv files
col_13_data(:,i) = table2array( data(:,13) ); % get the 13th column of each file
end
col_13_mean = mean(col_13_data ,2 ); % get the mean value for each row, over the files
##### 2 CommentsShowHide 1 older comment
Karim on 17 Jun 2022
ok i think i understand what you mean, i update the example code accordingly