Plot different Y values for certain range of X

Let's say I have:

X = [1:10];

Y = [10:20];

I want to plot Y vs X, but in the range of X=[5:10] I want Y values to be (Y+20). And have the same plot line for all.

How can I do it?

Answer 1

[Jonas]

you can just calculate the values before plotting

Y(X>=5 & X<=10)=Y(X>=5 & X<=10)+20;

[Paz Yedidim]

It is for analyzing big amount of data, and I will have to a edit Y values in several ranges of X.

Is there a more suitable way for it?