How do I extract specific data from an array inside a cell array using indexing?

19 次查看（过去 30 天）
Joel Peeters
Joel Peeters 2020-4-14
编辑： Ameer Hamza 2020-4-14
So I have a cell array B of size 4*101 in which each cell contains an array of size 1*3, like this:
B = cell([4 101]);
for i = 1:4
for ii = 1:101
B{i,ii} = rand([1 3]);
end
end
And I need to get the third element of the 1*3 arrays from all cells in the top row of the cell array. I can do that using
C = zeros(101,1)
for i = 1:101
C(i) = B{1,i}(3);
end
But since I need to extract this kind of data quite a lot it'd be a lot nicer to be able to do this in one line using indexing. I figured using
C = B{1,:}(3);
Should work but this gives the error
"Expected one output from a curly brace or dot indexing expression, but there were 101 results."
How do I index this so that it works?

请先登录，再回答此问题。

采纳的回答

Mehmed Saad
Mehmed Saad 2020-4-14
use cellfun
cellfun(@(x) x(3),B(1,:))

更多回答（2 个）

Peng Li
Peng Li 2020-4-14
d = cellfun(@(x) x(3), B);
d gives you the third element from all cells. You can index into d to find those that correspond to the first row.
Ameer Hamza
Ameer Hamza 2020-4-14
编辑：Ameer Hamza 2020-4-14
Use can use basic indexing operations in MATLAB without the need to call any function
B = cell([4 101]);
for i = 1:4
for ii = 1:101
B{i,ii} = rand([1 3]);
end
end
result = [B{1,:}];
result = result(3:3:end);

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

R2020a

Community Treasure Hunt

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

Start Hunting!

Translated by