# how to write if statement for matrix ?

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Ibrahim AlZoubi on 16 May 2020
Commented: Geoff Hayes on 18 May 2020
how to write if statement for matrix ?
in other words:
test= [5;6;0;-1;0]
this is the condition:
if test==0
disp 0
else
disp 5
end
and I want to give answer for each row (for 5 and 6 and 0 ....etc)

Geoff Hayes on 16 May 2020
Ibrahim - what are you trying to do here? Just display (with disp) a message depending upon whether an element is a zero or not? The simplest and least efficient way to do this is with a loop
test = [5;6;0;-1;0];
for k = length(test)
if test(k) == 0
disp 0;
else
disp 5;
end
end
I don't think that is what you really want though so you may need to provide more details. I also suspect that you shouldn't need to use a for loop and that may be the case depending upon the details you provide.

Ibrahim AlZoubi on 17 May 2020
I have two matrices first one is:
test = [5;6;0;-1;0;5;0;6;0;8];
and the second one is:
test5 = [2;6;8;-1;0;7;8;6;8;8];
how to generate third matrix which is the result after the condition (if statment)...
the condition is if the value of test is equal 0 then the value of the new matrix is 0 , else if the value of the first matrix isn't equal 0 do some calculations on the second matrix which is test5 like (test5*7+5).
so the third matrix values depends on the two matrix before...
Geoff Hayes on 18 May 2020
Is the output array of the same dimensions as test?
test = [5;6;0;-1;0];
outputArray = size(test);
for k = length(test)
if test(k) == 0
outputArray(k) = 0;
else
% do a calculation of some kind
outputArray(k) = 42; % <--- your code here
end
end