How to flatten and split and concatenate arrays in several files

Hello.

I want to flatten and split and concatenate arrays in several files.

For example,

I have several datasets (237 x 40, 238 x 40, 239 x 40 ....)

1. I want to flatten each dataset

(237 x 40 -> 1 x 9480 , 238 x 40 => 1 x 9520, 239 x 40 = > 1 x 9560)

2. I want to split each datasets to minimum length among datasets.

1 x 9480, 1 x 9480, 1 x 9480

3. concatenate (3 x 9480)

I can do as several codes, but I have lots of data.

So I want to reduce the code.

clear all
close all


X = csvread('boxing/boxing50.csv');
Y = csvread('boxing/boxing51.csv');
Z = csvread('boxing/boxing52.csv');

% flatten
X = reshape(X,[],1);
Y = reshape(Y,[],1);
Z = reshape(Z,[],1);

% find the minimum and split to the minimum length
X = X(:,1:9480)
Y = Y(:,1:9480)
Z = Z(:,1:9480)

% concatenate
All = [X; Y; Z]

[Kong]

Hello.

Before flattening each CSV file, I found that each file has a different size of the matrix.

(237 x 39 , 238 x 38 , 239 x 37 ...)

In other words, I want to find each minimum length of row and column and flatten them.

Before : 237 x 39 , 238 x 38 , 239 x 37 ...

After : 237 x 37 , 237 x 37 , 237 x 37 ...

Answer 1

[Akira Agata]

I think the following code can do that task:

By the way, your code will output 28440-by-1 (28440 = 9480 x 3), not the 3-by-9480. So the following code will generate N-by-1 array.

% Create the list of csv files
s = dir('boxing/*.csv');

% Read from each csv file
c = cell(numel(s),1);
for kk = 1:numel(s)
  filePath = fullfile(s(kk).folder,s(kk).name);
  x = csvread(filePath);
  c{kk} = x(:);
end

% Find the minumul length
len = cellfun(@numel,c);
minLen = min(len);

% Delete minLen+1:end for each array in cell
c = cellfun(@(x) x(1:minLen),c,'UniformOutput',false);

% Concatenate them
All = cell2mat(c);

[Kong]

Thank you so much!

As you mentioned, I got 28440-by-1.

How can I get type 3-by-9480?

[Kong]

Hello.

Before flattening each CSV file, I found that each file has a different size of the matrix.

(237 x 39 , 238 x 38 , 239 x 37 ...)

In other words, I want to find each minimum length of row and column and flatten them.

Before : 237 x 39 , 238 x 38 , 239 x 37 ...

After : 237 x 37 , 237 x 37 , 237 x 37 ...

[Akira Agata]

> How can I get type 3-by-9480?

By changing the last line by the following, you can obtain 9480-by-3 output array.

All = cell2mat(c');

So, in order to obtain 3-by-9480, you should simply transpose this, like:

All = cell2mat(c')';

[Kong]

Thank you so much!

I want to reduce each column and row as a minimum and then flatten them.

[Akira Agata]

Regarding the second question, how about the following?

% Create the list of csv files
% -> Same as the previous code

% Read from each csv file
% -> Same as the previous code

% Find the minumul number of row and column
row = cellfun(@(x) size(x,1),c);
col = cellfun(@(x) size(x,2),c);
minRow = min(row);
minCol = min(col);

% Adjust the size of each array to minRow-by-minCol
c = cellfun(@(x) x(1:minRow,1:minCol),c,'UniformOutput',false);

% Flatten them
c = cellfun(@(x) x(:),c,'UniformOutput',false);

% Concatenate them
All = cell2mat(c')';

[Kong]

I very much appreciate your help.

When I just use this part of code, I got a cell that already flattened array.

At this step, I want to get type N x M (296 x 40) and then find minumul number of row and column.

clear all
close all

% Create the list of csv files
s = dir('*.csv');
% Read from each csv file
c = cell(numel(s),1);
for kk = 1:numel(s)
  filePath = fullfile(s(kk).folder,s(kk).name);
  x = csvread(filePath);
  c{kk} = x(:);
end

[Akira Agata]

Oops!

Sorry, please change "c{kk} = x(:)" to "c{kk} = x".

[Kong]

Thank you so much!

I got it.