I am trying to create a character vector using a for loop?

I am trying to create a character vector using a for loop with a couple of if statements and my out out is coming out with NAN currently.

 A= Anodes;
x= extforce';
f1= A\x;
F= inv(A)*x;
F=round(F,6);
ten= "Tension";
comp= "Compression";
zfm= "ZeroForceMember";
Type= [];
for i= 1:length(F)
    if F(i,:)> 0 
        Type(i,:)= ten
    elseif F(i,:)< 0
        Type(i,:)= comp
    else 
        Type(i,:)= zfm
    end
end
Type
Mem= ["QA","AB","BC","CD","DE","EF","FP","GH","HJ","JK","KL","LM","GA","HB","JC","KD","LE","MF","GB","HC","JD","DL","ME","GQ","MP","QX","QY","PY"]';
table(Mem,F)

>> matlabproj12

Type =

   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN
   NaN

Answer 1

[KSSV]

   A= Anodes;
  x= extforce';
  f1= A\x;
  F= inv(A)*x;
  F=round(F,6);
  ten= "Tension";
  comp= "Compression";
  zfm= "ZeroForceMember";
  Type= cell(length(F),1) ;
  for i= 1:length(F)
      if F(i,:)> 0 
          Type{i}= ten
      elseif F(i,:)< 0
          Type{i}= comp
      else 
          Type{i}= zfm
      end
  end

Answer 2

[Ameer Hamza]

by initializing using

Type= [];

you are specifying it type as double. So by just removing this line, the code will work fine.

If you care about preallocation you can do this

Type= string(zeros(length(F),1));