# How to use if statement for than one variables?

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Ivan Mich on 4 Jul 2021
I would like to set one if statement. I am using the following code:
filename2= 'OutputFile1L.xlsx';
a=d2(:,1);
for ii=1:numel(a)
if a(ii)==0
b(ii)==1 & c(ii)==0
elseif a(ii)==1
b(ii)==0 & c(ii)==0
elseif a==2
b(ii)==0 & c(ii)==0
else
b(ii)==nan & c(ii)==nan
end
but command window shows me
Undefined function or variable b

Sulaymon Eshkabilov on 4 Jul 2021
Edited: Sulaymon Eshkabilov on 4 Jul 2021
Note that for loop and "if" based calcs are very slow and inefficient.
Anyhow if indeed you wish to fix your code, then check these corrected errs with ==, & |, , e.g:
for ii=1:numel(a)
if a(ii)==0
b(ii)=1; c(ii)=0;
elseif a(ii)==1 | a(ii)==2
b(ii)=0; c(ii)=0;
else
b(ii)=nan; c(ii)=nan;
end
end
##### 2 CommentsShowHide 1 older comment
Sulaymon Eshkabilov on 4 Jul 2021
@Image Analyst Very Good point and discussion! "Not Always" cases are small size simulation problems which require insignifcantly small amount of sim time.

Yongjian Feng on 4 Jul 2021
You meant this?
if a(ii)==0
b(ii)=1;
c(ii)=0;
elseif a(ii)==1
b(ii)=0;
c(ii)=0;
elseif a==2
b(ii)=0;
c(ii)=0;
else
b(ii)=nan;
c(ii)=nan;
end
Sulaymon Eshkabilov on 4 Jul 2021
There are a couple of ERRs in Feng's proposed code:
for ... % is missing
...
if ..
elseif a==2 % MUST be a(ii)==2
...
end
end

Sulaymon Eshkabilov on 4 Jul 2021
Edited: Sulaymon Eshkabilov on 4 Jul 2021
There are several errs in your loop code that is not advised. Just because it is slow and inefficient.
Here is an easy sol isntead of loop based code:
...
a=d2(:,1);
Idx0=find(a(:)==0);
Idx1=find(a(:)==1 | a(:)==2);
Idx2=find(a~=0 & a~=1 & a~=2);
b(Idx0)=1; c(Idx0)=0;
b(Idx1)=0; c(Idx1)=1;
b(Idx2)=nan; c(Idx2)=nan;