Iter rec - does it always have to be an integer?
2 views (last 30 days)
Show older comments
I'm just trying to set up some 'for' loops and I have a couple of arrays that don't go up in integer values. I've been using this kind of thing so far: -
iter=1;
for n=1:20;
y=n^2
yrec(iter)=y;
iter=iter+1;
end
How do I make it so the iter value is less than one?
1 Comment
Matt Fig
on 2 Nov 2012
I'm just trying to set up some 'for' loops and I have a couple of arrays that don't go up in integer values. I've been using this kind of thing so far: -
iter=1;
for n=1:20;
y=n^2
yrec(iter)=y;
iter=iter+1;
end
How do I make it so the iter value is less than one?
Accepted Answer
Walter Roberson
on 7 Jan 2012
You cannot use non-integer indices for arrays. Instead, (for example)
iter=1;
itervals = [];
for n=1:20;
y = n^2
yrec(n) = y;
itervals(n) = iter;
iter = iter + 0.123;
end
Then yrec(K) is the yrec that corresponds to location itervals(K)
4 Comments
Walter Roberson
on 9 Jan 2012
iter=1;
itervals = [];
for n=1:20;
y = n^2
yrec(n) = y;
itervals(n) = iter;
iter = iter + 0.1;
end
The "for" loop controls how many times to execute, and when you choose to have that loop start from 1 and increment by 1 (the default) then the loop variable also gives you the array index you want to use. But the array index is not the same as the value of the point represented -- just like in the slope example, x(1) does not mean x=1 but rather means "the first x". The array itervals that I showed in my example code is recording the actual values for the coordinate.
For example, the array x = [2, 5, 7] is indexed at 1, 2, and 3; x(1) is 2, x(2) is 5, x(3) is 7. If you were using y=x.^2 then the corresponding y would be [4, 25, 49], so you would read off
x(1) is 2 and y(1) corresponds to the function value evaluated at x(1)
x(2) is 5 and y(2) corresponds to the function value evaluated at x(2)
More Answers (0)
See Also
Categories
Find more on Loops and Conditional Statements in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!