# loop for matlab array

2 views (last 30 days)
best16 programmer on 23 Nov 2016
Edited: James Tursa on 23 Nov 2016
i have a problem with for loop.we have a vector a=[0 1 1 1 0] and a vector b=[1 1 1 1 1]
for i = 1:length(a)
if a(i)==0
c = [-1.*b] ;
else if a(i)==1
c = [1.* b];
end
end
the loop works only for a(1)=0 and stops.

Geoff Hayes on 23 Nov 2016
Try removing the space between the else if. Re-write this as
if a(i)==0
c = [-1.*b] ;
elseif a(i)==1
c = [1.* b];
end
Image Analyst on 23 Nov 2016
Then just do
handles.edit1.String = sprintf('%d ', c);
This will convert the vector to a string and put it into the edit text box on your GUI.

Image Analyst on 23 Nov 2016
Maybe you wanted elseif instead of "else if". This works and does several iterations:
a=[0 1 1 1 0]
b=[1 1 1 1 1]
for i = 1:length(a)
if a(i)==0
c = [-1.*b]
elseif a(i)==1
c = [1.* b]
end
end
Of course there are better ways to do that and no experienced MATLAB programmer would do that operation like that.
Image Analyst on 23 Nov 2016
They will all be displayed because there is no semicolon at the end of the line. Did you actually try it and look in the command window?

Andrei Bobrov on 23 Nov 2016
c = (a(:)*2 - 1)*b(:)';
or
c = (a(:)*2 - 1).*b(:);