MATLAB: Need help creating matrix (Easy)

for loopmatrix

A 5×7 matrix where each value is given by 'number of row x number of colon'

This is the matrix I want to create [1 2 3 4 5 6 7 2 4 6 8 10 12 14 3 6 9 12 15 18 21 4 8 12 16 20 24 28 5 10 15 20 25 30 35]

First off, I am completely new to this. I tried to go about it in one step, by creating two for loops; however, I am stuck because the values do not grow by the same amount for rows/columns.

Any help is greatly appreciated!

Best Answer

Try this:

for column = 1 : 7
  for row = 1 : 5
    result(row, column) = row * column;
  end
end
% Print to command window:
result

Related Solutions

MATLAB: Random matrix with maximum values.

You could do this:

w = floor(sqrt(30))
rows = 1 : w
counter = 1;
for k = 1 : length(rows)
	columns(k) = floor(30/rows(k));
	for col = 1 : columns(k)
		fprintf('For %d rows, and %d columns, there are %d elements.\n',...
			rows(k), col, rows(k) * col);
		allMatrices{counter} = rand(rows(k), col);
		counter = counter + 1;
	end
end

You'll get every possible matrix size with 30 or fewer elements in it. And each one will be a cell in the allMatrices cell array. It has to be a cell array rather than a 3-D matrix because the matrices are not all the same size. You'll see in the command window:

w =

rows =

1 2 3 4 5

For 1 rows, and 1 columns, there are 1 elements.

For 1 rows, and 2 columns, there are 2 elements.

For 1 rows, and 3 columns, there are 3 elements.

For 1 rows, and 4 columns, there are 4 elements.

For 1 rows, and 5 columns, there are 5 elements.

For 1 rows, and 6 columns, there are 6 elements.

For 1 rows, and 7 columns, there are 7 elements.

For 1 rows, and 8 columns, there are 8 elements.

For 1 rows, and 9 columns, there are 9 elements.

For 1 rows, and 10 columns, there are 10 elements.

For 1 rows, and 11 columns, there are 11 elements.

For 1 rows, and 12 columns, there are 12 elements.

For 1 rows, and 13 columns, there are 13 elements.

For 1 rows, and 14 columns, there are 14 elements.

For 1 rows, and 15 columns, there are 15 elements.

For 1 rows, and 16 columns, there are 16 elements.

For 1 rows, and 17 columns, there are 17 elements.

For 1 rows, and 18 columns, there are 18 elements.

For 1 rows, and 19 columns, there are 19 elements.

For 1 rows, and 20 columns, there are 20 elements.

For 1 rows, and 21 columns, there are 21 elements.

For 1 rows, and 22 columns, there are 22 elements.

For 1 rows, and 23 columns, there are 23 elements.

For 1 rows, and 24 columns, there are 24 elements.

For 1 rows, and 25 columns, there are 25 elements.

For 1 rows, and 26 columns, there are 26 elements.

For 1 rows, and 27 columns, there are 27 elements.

For 1 rows, and 28 columns, there are 28 elements.

For 1 rows, and 29 columns, there are 29 elements.

For 1 rows, and 30 columns, there are 30 elements.

For 2 rows, and 1 columns, there are 2 elements.

For 2 rows, and 2 columns, there are 4 elements.

For 2 rows, and 3 columns, there are 6 elements.

For 2 rows, and 4 columns, there are 8 elements.

For 2 rows, and 5 columns, there are 10 elements.

For 2 rows, and 6 columns, there are 12 elements.

For 2 rows, and 7 columns, there are 14 elements.

For 2 rows, and 8 columns, there are 16 elements.

For 2 rows, and 9 columns, there are 18 elements.

For 2 rows, and 10 columns, there are 20 elements.

For 2 rows, and 11 columns, there are 22 elements.

For 2 rows, and 12 columns, there are 24 elements.

For 2 rows, and 13 columns, there are 26 elements.

For 2 rows, and 14 columns, there are 28 elements.

For 2 rows, and 15 columns, there are 30 elements.

For 3 rows, and 1 columns, there are 3 elements.

For 3 rows, and 2 columns, there are 6 elements.

For 3 rows, and 3 columns, there are 9 elements.

For 3 rows, and 4 columns, there are 12 elements.

For 3 rows, and 5 columns, there are 15 elements.

For 3 rows, and 6 columns, there are 18 elements.

For 3 rows, and 7 columns, there are 21 elements.

For 3 rows, and 8 columns, there are 24 elements.

For 3 rows, and 9 columns, there are 27 elements.

For 3 rows, and 10 columns, there are 30 elements.

For 4 rows, and 1 columns, there are 4 elements.

For 4 rows, and 2 columns, there are 8 elements.

For 4 rows, and 3 columns, there are 12 elements.

For 4 rows, and 4 columns, there are 16 elements.

For 4 rows, and 5 columns, there are 20 elements.

For 4 rows, and 6 columns, there are 24 elements.

For 4 rows, and 7 columns, there are 28 elements.

For 5 rows, and 1 columns, there are 5 elements.

For 5 rows, and 2 columns, there are 10 elements.

For 5 rows, and 3 columns, there are 15 elements.

For 5 rows, and 4 columns, there are 20 elements.

For 5 rows, and 5 columns, there are 25 elements.

For 5 rows, and 6 columns, there are 30 elements.

MATLAB: How to rearrange data in matrix rows

reshape, like pretty much all MATLAB operations, works columnwise. So you just need to transpose, reshape, transpose:

X = [20031119 1 2 3 4 5 6 7 8 9;
10 11 12 13 14 15 16 17 18 19;
20 21 22 23 24 25 26 27 28 29;
30 31 NaN NaN NaN NaN NaN NaN NaN NaN;
20031120 1 2 3 4 5 6 7 8 9;
10 11 12 13 14 15 16 17 18 19;
20 21 22 23 24 25 26 27 28 29;
30 31 NaN NaN NaN NaN NaN NaN NaN NaN];
out = reshape(X.',[],size(X,1)/4).';

creates this output matrix:

>> out
out =
 Columns 1 through 9:
   20031119          1          2          3          4          5          6          7          8
   20031120          1          2          3          4          5          6          7          8
 Columns 10 through 18:
          9         10         11         12         13         14         15         16         17
          9         10         11         12         13         14         15         16         17
 Columns 19 through 27:
         18         19         20         21         22         23         24         25         26
         18         19         20         21         22         23         24         25         26
 Columns 28 through 36:
         27         28         29         30         31        NaN        NaN        NaN        NaN
         27         28         29         30         31        NaN        NaN        NaN        NaN
 Columns 37 through 40:
        NaN        NaN        NaN        NaN
        NaN        NaN        NaN        NaN

Best Answer

Related Solutions

MATLAB: Random matrix with maximum values.

MATLAB: How to rearrange data in matrix rows

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