File and array manipulation.

I have one file that contains multiple arrays of similar dimensions. How can I add the cells from each array to generate a single array of the same dimension that represents the mean or median value for each cell?

4 Comments

how many array do you have? and what is the size of your result array?
Just so we understand. Your array is a cell array, or a numerical array? You say
"How can I add the cells from each array"
but do you mean you want to add the elements from each array? In MATLAB a cell array is a particular thing, and if you don't have a cell array, you shouldn't refer to cells but instead to elements.
Thanks for your quick response. There are 365 arrays. Each array is 216 x 104.
sorry, i'm very new to matlab. i read the array using xlsread(). the arrays are found in a single file and each element (say row1, col1)represents a value i'd like to manipulate in each of the 365 arrays. so, i'd like to add the element contained in row1, col1 from array 1 to row1, col1 in array 2. i tried using multidimensional array functions.

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Answers (2)

Azzi Abdelmalek
Azzi Abdelmalek on 17 Aug 2012
Edited: Azzi Abdelmalek on 17 Aug 2012
A=xlsread('YourFileName');
[n,m]=size(A);
M=reshape(A,105,m,n/105), % now you array (105,216,365)
M(105,:,:)=[]; %eliminate the separating row
% the first matrix is M(:,:,1)
% the second is M(:,:,2)
% ...

11 Comments

Thanks for your quick response. There are 365 arrays. Each array is 216 x 104.
sorry, i'm very new to matlab. i read the array using xlsread(). the arrays are found in a single file and each element (say row1, col1)represents a value i'd like to manipulate in each of the 365 arrays. so, i'd like to add the element contained in row1, col1 from array 1 to row1, col1 in array 2. i tried using multidimensional array functions.
can you post your code readind xls file ?
if you wrote
num=xlsread('YourFileName')
can you tell us what are size of num?
xlsread('Netrech_2002.xlsx') ...i haven't developed code yet. the file is large. where do you prefer i post it?
We need to understand it's size. You don't need to post it.
Also, I understand you're manually importing 365 excel files?
you said that your file contains many arrays, but when you read it, you import just one cell array. do you mean that this cell array contains many array. to extract them we must know what is the size of this cell array, just do
num=xlsread('YourFileName')
[n,m]=size(num)
and tell us what are n and m
I am reading one file that contains 365 arrays separated by a row. Each array contains 216 columns, and 104 rows.
n = 38325 = number of rows containing groundwater recharge values m = 216 = number of columns containing groundwater recharge values
this is what's returned. >> A=cell2mat(num) contents reference from a non-cell array object.
Error in cell2mat (line 43) cellclass = class(c{1});
Azzi Abdelmalek
Azzi Abdelmalek on 17 Aug 2012
Edited: Azzi Abdelmalek on 17 Aug 2012
sorry, num is not a cell array,
i have updated an the answer
Thanks Azzi. It looks like my array has been reshaped. I have to run out for the day, but will run your new answer.

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Consider the matrices of the same size as the matrix a.
s = size(a);
k = whos;
n = find(strcmp({k.class},'double'));
m = {k.size};
t = {k(n(cellfun(@(x)isequal(x,s),m(n)))).name};
val = eval(['[',cell2mat(strcat(t,'(:);')),']']);
out = accumarray(repmat(fullfact(s),numel(t),1),val,[],@mean);

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on 17 Aug 2012

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