recode the missing values equal to the preceding recorded value

hello,

I am doing assienment and having some problem

there is a matrix:

anuual_CO2 = [ 1990 339; 1991 339.1; 1992 338.8; 1993 -999; 1994 339.5; 1995 338; 1996 -999; 1997 -999; 1998 -999; 1999 339.5; 2000 337.9]

in this matrix, it should recode '-999' which are missing values.

I need to draw a plot, set missing values equal to the preceding recorded value

how to set -999 as the previous numbers in the plot without type the number dierectly

thank you for helping in advance

Answer 1

[Guillaume]

The easiest way is to use fillmissing with the appropriate option, after having replaced the -999 by NaN.

Answer 2

[R.G.]

Hello! You can use following code:

a = [ 1990 339; 1991 339.1; 1992 338.8; 1993 -999; 1994 339.5; 1995 338; 1996 -999; 1997 -999; 1998 -999; 1999 339.5; 2000 337.9];
for i = 1:length(a)
    if a(i,2) == -999 && i > 1
        a(i,2) = a(i-1,2);
    end
end

Answer 3

[Andrei Bobrov]

lo = anuual_CO2(:,2) ~= -999;
x = anuual_CO2(lo,2);
anuual_CO2(:,2) = x(cumsum(lo));