Indexing of cell array and a vector

6 次查看（过去 30 天）
Sergio Rojas Blanco
评论： Sergio Rojas Blanco 2024-6-3
Hi guys, my problem has been raised before but with some differences.
I have a cell array of indexes, index. Its cells can be zero or vectors with several values. On the other hand I have a data vector, data. I need a cell array, out, that relates data to indexes, preferably without using a loop.
For example:
index = {[0], [0], [5], [0], [6, 7], [0], [0], [1], [0], [0], [0], [ 3]} ;
data = [100, 10, 20, 15, 11, 25, 200, 45];
Desired result:
out = {[0], [0], [11], [0], [25, 200], [0], [0], [100], [0], [0], [20]}
Can somebody help me?
  4 个评论
显示 2更早的评论
Stephen23
Stephen23 2024-6-2
编辑：Stephen23 2024-6-2
"I think a loop would be slower, right?"
A well-written FOR-loop would likely be faster than code using CELLFUN, ARRAYFUN, or anything else.
Who taught you the oddly-persistent myth that FOR-loops are slow?
Sergio Rojas Blanco
Sergio Rojas Blanco 2024-6-3
Actually, I don't know the internal process of cellfun or arrayfun. Possibly, they perform a loop and, therefore, it would be difficult to choose the most efficient procedure, but I don't know, and I have assumed that loops take longer. It would have to be checked experimentally.
In any case, I thank you very much for your contributions. They have helped me a lot

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2024-6-2
Ran in:
One approach —
index = {[0], [0], [5], [0], [6, 7], [0], [0], [1], [0], [0], [0], [ 3]} ;
data = [100, 10, 20, 15, 11, 25, 200, 45];
q = cellfun(@(x) data(x(x>0)), index, 'Unif',0);
Lvc = cellfun(@(x) all(x==0), index, 'Unif',0); % Using 'all' Is Necessary To Make The Logical Indices Work Correctly
out = index;
out(~[Lvc{:}]) = q(~[Lvc{:}])
out = 1x12 cell array
{[0]} {[0]} {[11]} {[0]} {[25 200]} {[0]} {[0]} {[100]} {[0]} {[0]} {[0]} {[20]}
.

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 的更多信息

标签

产品


版本

R2024a

Community Treasure Hunt

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

Start Hunting!

Translated by