How to combine sections from Workspace into a new vector?

I have Matlab 2017b.

1) If we have two vectors A and B, in the workspace (1000x1), each of same dimension. How can one combine certain sections of A and B to form a new vector D (1000x1), by taking desired data of interest from A and B?

Is there a simple way to achieve this?

2) If we have a vector (1000 x 3) in the workspace, how can we define a new variable Z which contains selected data from an ith row to jth row from vector (1000x3)?

Thank you.

Answer 1

[madhan ravi]

Yes ,simply use basic indexing:

% 1)

D = [A(1:500);B(1:500)] % example

% 2)

ith_row = 400;
jth_row = 700;
Z = matrix(ith_row:jth_row,:) % matrix is of size 1000 X 3

[FW]

Thank you. Let me clarify my second part. I wanted to say if we have workspace data in 1000x3, but we wish to selectively extract some data from certain row elements, say from row 200 to 400 but from column 1 only to form a new vector. What syntax can we use? Thanks.

[madhan ravi]

data(200:400,1)

[FW]

Thanks. Where will we place the variable name? If we have multiple datasets in the workspace, how will it the data (200:400, 1) command recognize the data set.

[madhan ravi]

data is the name of the variable that you want to extract. For example if you have variable named Z which is of size 1000 X 3 then

Z(200:400,1)