I need to replace some values with NaN and some values with zeros

Hi every one can help

in annexed figure I have table in left handside gives its corresponding curves and I want to replace some values in z1, z2, and z3 to be NaN and replace some values of zb to be zeros by using Matlab If -Condition ro get the right handside that gives the corresponding curves

Thanks in advance

M. Dahab

[Arif Hoq]

what is the condition?

if gBt >= any value
    z1= ????
elseif gBt == any value
    z2= ????
end

[Moustafa Abedel Fattah]

Can you please use the excel file attached with Voss answer and write the complite code

Answer 1

[Voss]

I've entered the values from your left-hand table into Excel and saved the attached xlsx file.

Read the file into a matrix and plot z1, z2, z3, and zb vs xc:

M = readmatrix('data.xlsx');

figure();
plot(M(:,1),M(:,3:end))
set(gca(),'YDir','reverse');

Modify the matrix by replacing certain elements with 0 or NaN:

% where gBt is not close to 0.808269 ...
idx = abs(M(:,2) - 0.808269) > 1e-6;

% ... replace z1, z2, z3 with NaN ...
M(idx,3:end-1) = NaN;

% ... and replace zb with 0
M(idx,end) = 0;

Plot again, with new M for comparison:

figure();
plot(M(:,1),M(:,3:end))
set(gca(),'YDir','reverse');

You can use similar steps on your data.

[Moustafa Abedel Fattah]

Thanks it is good and work and hope another answer with using if-condition

[Voss]

If you must use an if condition:

M = readmatrix('data.xlsx');

figure();
plot(M(:,1),M(:,3:end))
set(gca(),'YDir','reverse');

for ii = 1:size(M,1)
    if abs(M(ii,2) - 0.808269) > 1e-6
        % where gBt is not close to 0.808269
        % replace z1, z2, z3 with NaN ...
        M(ii,3:end-1) = NaN;
        % ... and replace zb with 0
        M(ii,end) = 0;
    end
end

figure();
plot(M(:,1),M(:,3:end))
set(gca(),'YDir','reverse');

[Moustafa Abedel Fattah]

Thanks very much and appreciet your effort for helping me

it work exactly as I want in

[Voss]

You're welcome! Any questions, let me know. Otherwise, please "Accept This Answer". Thanks!

[Moustafa Abedel Fattah]

Dear

I don't know if I would be annoying if I asked for a solution to the problem using If.....and......Swap. Thanks in advance.

[Voss]

What do you mean by "Swap"? I've showed a solution using "if", in a comment above.

[Moustafa Abedel Fattah]

I mean by "swap" as a Matlab order to clean the cell value and then replace with another value if satisfied the condition "if"

thanks for your paying me attention

[Voss]

You can substitute "another value" you want to use in place of the NaN in the code above.