Replacing NaN with value in previous column

Hi there, I am new in matlab and try to solve this problem for couple of hours, I need to replace all NaNs with the value in previous column and add 100:

so now I have> [14] [NaN] [9] [NaN] [13] [NaN] [13] [NaN] [9] [NaN] [15] [NaN] [11] [NaN] [10]

and I need to have> [14] [114] [9] [109] [13] [113] [13] [113] [9] [109] [15] [115] [11] [111] [10]

Thank you in advance.

Answer 1

[the cyclist]

Here is one way:

V = [9 nan 14 nan];
idx = find(isnan(V));
V(idx) = V(idx-1) + 100;

[the cyclist]

Note that this will break if the first value is NaN, but that seems logical since you would need a different rule for that case.

[Rene Sebena]

Cool, thank you very much.

Answer 2

[goerk]

Very simple solution/idea:

I suppose you have a vector

 v = [14 NaN 9 NaN 13 NaN];

you can get a Mask with the positions of the NaN's

 mask = isnan(v);

shift this mask one position to the left

 maskValue = [mask(2:end) false];

now you can create the new vector

 v2 = v;
 v2(mask) = v(maskValue)+100;

Attention: Special cases (e.g. two NaN's in a row, or a NaN at the beginning) has to be handled.

[goerk]

The Idea behind the proposed solutions are the same. But the two answers before need less code.

[Rene Sebena]

Thanks, okay this works, and what if the vector that I want to change, let´s say "v" is located in structure variable let´s say A?

[goerk]

Do you mean something like

 A.v = [14 NaN 9 NaN 13 NaN];

?