I have a data X say
X= 1:100 (integer 1 to 100)
I want to write a for loop that will create matrix of w=10x5 (10rows, 5 columns) where by column 1 will be the first 10 elements of X (1 to 10), column 2 (11 to 20) and so on and then stop at column 5 (41 to 50) before creating another matrix say w2 (ie starting the iteration again).
I don't want to use reshape function as it won't fit into the real data I am working on.

4 Kommentare

Matt J
Matt J am 6 Feb. 2022
I don't want to use reshape function as it won't fit into the real data I am working on.
No, the reshape() function is exactly the thing to use for what you're talking about. What do you mean "it won't fit"?
Cutie
Cutie am 6 Feb. 2022
Because, I may need to create matrix of size 9 by 5. In which case I will only have 2 matrices formed from the first 90 elements (1:90) and the last 10 element can be discarded.
Image Analyst
Image Analyst am 6 Feb. 2022
Bearbeitet: Image Analyst am 6 Feb. 2022
For 90, what are the sizes of the two matrices?
  1. 9-by-5? (in which case, my answer below works)
  2. Or one matrix of 10-by-5 and the second one of 10-by-4?
Cutie
Cutie am 7 Feb. 2022
I appreciate @Matt J and @Image Analyst for offering your help.

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 Akzeptierte Antwort

Matt J
Matt J am 6 Feb. 2022
Bearbeitet: Matt J am 6 Feb. 2022

1 Stimme

Because, I may need to create matrix of size 9 by 5. In which case I will only have 2 matrices formed from the first 90 elements (1:90) and the last 10 element can be discarded.
That doesn't disqualify reshape.
rows=9;
cols=5;
X=1:100;
M=rows*cols;
N=numel(X);
X=reshape( X(1:floor(N/M)*M) ,rows,cols,[]);
w=squeeze(num2cell(X,[1,2]))
w = 2×1 cell array
{9×5 double} {9×5 double}

1 Kommentar

Cutie
Cutie am 7 Feb. 2022
Thank you very much @Matt J. This works and it opens my eyes to other things.

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Weitere Antworten (1)

Image Analyst
Image Analyst am 6 Feb. 2022
Bearbeitet: Image Analyst am 6 Feb. 2022

0 Stimmen

Try this
N = 100; % or 90 or some other multiple of 10
X= 1 : N; % (integer 1 to 100)
x1 = reshape(X(1:N/2)', N/10, [])
x1 = 10×5
1 11 21 31 41 2 12 22 32 42 3 13 23 33 43 4 14 24 34 44 5 15 25 35 45 6 16 26 36 46 7 17 27 37 47 8 18 28 38 48 9 19 29 39 49 10 20 30 40 50
x2 = reshape(X(N/2+1:end), N/10, [])
x2 = 10×5
51 61 71 81 91 52 62 72 82 92 53 63 73 83 93 54 64 74 84 94 55 65 75 85 95 56 66 76 86 96 57 67 77 87 97 58 68 78 88 98 59 69 79 89 99 60 70 80 90 100
If you don't want to use reshape for some weird reason, you can do it with a for loop but it will be more complicated.
X = 1 : 100;
x3 = zeros(10, 5);
x4 = zeros(10, 5);
k = 1;
for col = 1 : 5
for row = 1 : 10
x3(row, col) = X(k);
x4(row, col) = X(k + 50);
k = k + 1;
end
end
x3
x3 = 10×5
1 11 21 31 41 2 12 22 32 42 3 13 23 33 43 4 14 24 34 44 5 15 25 35 45 6 16 26 36 46 7 17 27 37 47 8 18 28 38 48 9 19 29 39 49 10 20 30 40 50
x4
x4 = 10×5
51 61 71 81 91 52 62 72 82 92 53 63 73 83 93 54 64 74 84 94 55 65 75 85 95 56 66 76 86 96 57 67 77 87 97 58 68 78 88 98 59 69 79 89 99 60 70 80 90 100

3 Kommentare

Cutie
Cutie am 7 Feb. 2022
Thank you for offering your help.
Navita
Navita am 21 Feb. 2023
Output not showing
Image Analyst
Image Analyst am 21 Feb. 2023
@Navita as you can see above there is an output. I ran it in the editor with the green run triangle and there is definitely an output. Just look at my Answer and you can see it.
If you don't have any output then you must have copied my code and changed it somehow.
If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:

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am 6 Feb. 2022

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am 21 Feb. 2023

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