How do I use the OR "||" operator in an 'if' statement on multiple possible strings?

Hello, I am looking to categorize a collection of strings that I have stored in a vector ('Names') depending on their values. For example, for each element in the vector (which is a string, such as 'Na', or 'K', or 'Pb', etc.) if the element is a certain type of element I want to do something, whereas if it is a different type of element I want to do something else. I understand how to do this for scalar values using an 'if' statement, but there is the common error that pops up if the if statement uses the OR '||' operator on strings instead: "Operands to the || and && operators must be convertible to logical scalar values.".

This is what I am trying to do:

for i = 1:length(Names)
    if Names(i) == 'Pu' || 'Am' || 'Np' || 'Cm' ; %actinides
        Yield.CData(i,:) = [255 0 0]; %red for actinides
    elseif Names(i) == 'Mo' || 'Ru' || 'Tc' || 'Rh' ; %noble metals
        Yield.CData(i,:) = [0 255 0]; %green for noble metals
    elseif Names(i) == 'Ce' || 'Nd' || 'Eu' || 'Sm'  ; %lanthanides (R.E.E.)
        Yield.CData(i,:) = [255 255 0]; %yellow for lanthanides (R.E.E.)
    elseif Names(i) == 'Li' || 'Na' || 'K' || 'Rb' || 'Cs' || 'Fr' ;  %alkali-metal halides
        Yield.CData(i,:) = [0 0 0];  %black for alkali-metal halides
    else if Names(i) == 'O' || 'Xe' || 'Te'; %non-metals
        Yield.CData(i,:) = [255 255 255];  %white for non-metals
        else
        end
    end
end

If someone could please give me an answer or some insight I would very grateful!

~ Dan

Answer 1

[Kevin Phung]

I would suggest using switch / case, it's a lot more intuitive to look at:

for i = 1:length(Names)
    switch Names(i)
        
        case{'Pu','Am','Np','Cm'}
            Yield.CData(i,:) = [255 0 0];
        case{'Mo','Ru','Tc','Rh'}
             Yield.CData(i,:) = [0 255 0]; 
        case{'Ce','Nd','Eu','Sm'}
             Yield.CData(i,:) = [0 255 0]; 
        case{'Li','Na','K','Rb','Cs','Fr'}
            Yield.CData(i,:) = [0 0 0];
        case{'O','Xe','Te'}
             Yield.CData(i,:) = [255 255 255];  
    end
end

if you really wanted to use the if / else method, you should use strcmp:

if any(strcmp(a,{'Pu','Am','Np','Cm'}))
    %...
end

[Dan Hallatt]

This worked beautifully thank you. I had never heard of switch/case before but it seems quite powerful after a quick read on it. Thank you! I will impliment this into many other parts of my code to add flexibility.

[Kevin Phung]

you're welcome! happy to help.