how to combine two matrices?

A=[Pg; 0.5;0.6;0;0;0]

B=[0;0;0;0.7;0.7;0.7]

1)the answer i need is C=[Pg;0.5;0.6;0.7;0.7;0.7]

i tried C=[A,B] but thats not what i want.

2)how can i add zero to matrix D if first value of A is Pg.

Answer 1

[Les Beckham]

Maybe this is what you want for #1:

Pg = 1; % example value for Pg
A=[Pg; 0.5;0.6;0;0;0]

A = 6×1

1.0000 0.5000 0.6000 0 0 0

B=[0;0;0;0.7;0.7;0.7]

B = 6×1

0 0 0 0.7000 0.7000 0.7000

C = A+B

C = 6×1

1.0000 0.5000 0.6000 0.7000 0.7000 0.7000

For #2:

if A(1) == Pg
    % Do something to D
end

[arian hoseini]

is there any other way?

thats my problem i dont want to sum them because Pg may be a negtaive or positive value ..and if i sum them there will be a new value...

[Les Beckham]

It really depends on what you want to do. In the specific example you give in the question the first three elements of B and the last three elements of A are zero so adding them essentially replaces those elements. This is true regardless of the sign of Pg.

If you want to combine a portion of A with a portion of B you could do something like this:

Pg = 1; % example value for Pg
A = [Pg; 0.5; 0.6; 2; 2; 2]; % note that I've replaced the zeros with twos as an example
B = [2; 2; 2; 0.7; 0.7; 0.7];
C = [A(1:3); B(4:6)]

C = 6×1

1.0000 0.5000 0.6000 0.7000 0.7000 0.7000

Note that we get the first three elements of A and the last 3 elements of B.

To learn more of the basics of Matlab (indexing is especially relevant to your questions), I suggest that you take advantage of the free online training available here: https://www.mathworks.com/learn/tutorials/matlab-onramp.html

[arian hoseini]

thank u ...u are a life savior.