STORAGE OF SELECTIVE VALUES OF SOME CELLS INTO A SINGLE MATRIX FROM TWO DIFFERENT MATRICES. Whats wrong with this?

%Matrices Given
A = [1 2 3 4 5;6 7 8 9 10;1 4 5 6 7;8 9 44 5 6;5 5 16 25 44];
B = [3 4 16 44 66;16 25 33 44 66;20 31 45 66 80;11 22 33 44 55;7 10 25 44 60];

%Storage of a Matrix
C = [A(:,1)<4 & A(:,1)>=2;B(:,1)>4 & B(:,1)<40;A(:,2)<10 & A(:,2)>7;B(:,2)>=25 & B(:,2)<50];

What i expected was?

C =

2

3

16

8

9

25

33

44

But all i get is zeros and ones, Why? is it not the right way?

[William Alberg]

"A(:,1)<4 & A(:,1)>=2" only creates a logical matrix. You need to use the logical matrix to select values. Something like "A(A(:,1)<4 & A(:,1)>=2,1)"

[Sandip Ghatge]

I tried your suggestion, that just returns 1.

Answer 1

[William Alberg]

Okay, you have made 2 errors:

1. A(:,1) returns: [1;6;1;8;5]. I think you want it to return [1, 2, 3, 4, 5], which is A(1,:).
2. "A(:,1)<4 & A(:,1)>=2" gives an index, you want the corresponding values, which is: "A(A(:,1)<4 & A(:,1)>=2,1)" (Note that error 1 isn't fixed here)

You will need to understand this, otherwise you will make the same error again.

Since this appears to be for a school assignment, i will only correct the first section, you will need to the others yourself

C = [A(1,A(1,:) < 4 & A(1,:) >= 2)];

[Sandip Ghatge]

I completely understand the first blunder i made, as you mentioned in sentence 1.

and regarding second, i was trying to apply the condition for first column of matrix A, as mentioned in the code below,

C = [A(A(:,1) < 6 & A(:,1) > 1),1];

This is returning some unusual values, as [2,5;6,10;1,7;8,6;5,44]

Can you give me some hint as to where i went wrong here too.

Also, can you suggest me some matlab concepts which i can go through to get an inch closer to achieve the results desired,

Thank you.

[William Alberg]

Sorry, i dont follow?

Can you upload the code used to generate [2,5;6,10;1,7;8,6;5,44]

[Sandip Ghatge]

I am sorry, it was my mistake, actually the following code gave the above results,

A = [2 6 3 9 5;6 7 8 9 10;1 4 5 6 7;8 9 44 5 6;5 5 16 25 44];
B = [3 4 16 44 66;16 25 33 44 66;20 31 45 66 80;11 22 33 44 55;7 10 25 44 60];

C = [A(:,A(:,1) < 6 & A(:,1) > 1)];

Whereas, this code (Which has C defined as a single column matrix) returns error saying Dimensions of arrays being concatenated are not consistent.

A = [2 6 3 9 5;6 7 8 9 10;1 4 5 6 7;8 9 44 5 6;5 5 16 25 44];
B = [3 4 16 44 66;16 25 33 44 66;20 31 45 66 80;11 22 33 44 55;7 10 25 44 60];

C = [A(A(:,1) < 6 & A(:,1) > 1),1];

Both being unable to get desired results.

[William Alberg]

I am a bit confused about what you are trying to achieve in the first example. And i also dont understand why the numbers have changed. i think you want it to be:

C = [A(A(:,1) < 6 & A(:,1) > 1,1)]

However, that does not give the result you desired in your first post.

Your second example has a mistake in the last 5 characters. You have "),1];". It needs to be ",1)];"

Again, that does not give the result you originally specified.

The code below is your original solution, with my first answer inserted. ( I changed the layout a bit)

C = [...
	A(1,A(1,:) < 4 & A(1,:) >= 2)';...
	B(:,1)>4 & B(:,1)<40;... % needs change
	A(:,2)<10 & A(:,2)>7;... % needs change
	B(:,2)>=25 & B(:,2)<50]; % needs change

[Sandip Ghatge]

Sorry, for confusing you.

I have got my desired results, and have written such codes for both columns of A & B.

Thank you very much.