Clear Filters
Clear Filters

Change Array Name In Each Loop

18 views (last 30 days)
Matthew
Matthew on 9 Oct 2017
Commented: Matthew on 9 Oct 2017
I'm writing a For loop and want to create an array each loop, with the name changed according to the loop counter; e.g., Coll1, Coll2, Coll3, etc. Before folks slaughter me for asking...I've already read on here where folks have asked the question and "experts" recoil sharply against them saying it's a very bad newbie idea. Instead they should use the same array name but use indexing. I get that. But in this case I don't think I can do that because in each iteration of the loop, the newly created array has different dimensions each time. So I don't want the largest one creating a slew of zero cells in the smaller ones just for the sake of using a single array name. Any tips on how I can do this?
Thanks in advance, M Ridzon
  2 Comments
per isakson
per isakson on 9 Oct 2017
Edited: per isakson on 9 Oct 2017
Possibilities
  1. Assign "newly created array has different dimensions each time" to a new cell in a cell array
  2. Assign each array to a new field in a structure. Better alternative if you have descriptive names for the arrays. Its easier to remember good names than numbers. Your code will be easier to read.
If you present good reasons for not using one of these two, I will answer questions on eval.
Matthew
Matthew on 9 Oct 2017
#1 sounds like a great idea. I hadn't thought of that. Thanks!

Sign in to comment.

Accepted Answer

Steven Lord
Steven Lord on 9 Oct 2017
As per suggested, use a cell array.
C = cell(1, 10);
for n = 1:10
C{n} = rand(n); % size(C{n}) is [n n]
end
Each cell in C has a different sized matrix.
  1 Comment
Matthew
Matthew on 9 Oct 2017
I didn't think of this. Great idea! Thanks!

Sign in to comment.

More Answers (1)

Image Analyst
Image Analyst on 9 Oct 2017
So? Simply have 3 for loops and create a new array in each one. What's the problem?
for k = 1 : whatever1
Coll1(k) = whatever2;
end
for k = 1 : whatever3
Coll2(k) = whatever4;
end
for k = 1 : whatever5
Coll3(k) = whatever6;
end
There's absolutely nothing wrong with that - no shame. Just go ahead and do it.
  1 Comment
Matthew
Matthew on 9 Oct 2017
Thanks, but this won't work. I do not know beforehand how many times FOR will run; i.e., the ending iteration changes. Therefore, Coll<end#> is unknown.

Sign in to comment.

Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!