Add first element to a cell array

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Luis Isaac
Luis Isaac 2015-12-18
编辑： Fletcher Garrison 2021-2-3
Dear,
I would like to add a new element in the first position in an cell array For example if ArrCell={[1],[2],[3],[4],[5]} is the existing cell and [new] is a matrix. I would like to get ArrCell={[new],[1],[2],[3],[4],[5]}
Of course, I can get this result using a temporal cell array and looping over all the elements of the existing one, but the quesion is if there an efficient way to get this result
Thanks in advance,

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Adam
Adam 2015-12-18
ArrCell = [ { new }, ArrCell ];
should work. I'm not at my machine with Matlab at the moment so can't double-check, but fairly sure that works.
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Adam
Adam 2020-3-20
ArrCell was a row array. You can't concatenate vertically a scalar and a 5-element row array.
Image Analyst
Image Analyst 2020-3-20
new = magic(3) % A matrix
ArrCell={[1],[2],[3],[4],[5]} % A cell array
ArrCell = [ { new }, ArrCell ] % Adam uses comma
ArrCell2 = [ { new }; ArrCell ]; % Daniel uses semicolon
new =
8 1 6
3 5 7
4 9 2
ArrCell =
1×5 cell array
{[1]} {[2]} {[3]} {[4]} {[5]}
ArrCell =
1×6 cell array
{3×3 double} {[1]} {[2]} {[3]} {[4]} {[5]}
Error using vertcat
Dimensions of arrays being concatenated are not consistent.
Error in test1 (line 12)
ArrCell2 = [ { new }; ArrCell ];

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更多回答（2 个）

Image Analyst
Image Analyst 2015-12-18
But the big question is why are you even using a cell array for that instead of a simple numerical array. Cell arrays are complicated and use a huge amount of overhead. From what you've shown there is no reason to use one. I recommend this instead
Arr = [1,2,3,4,5];
Arr = [new, 1,2,3,4,5]
  1 个评论
Luis Isaac
Luis Isaac 2015-12-18
I using a cell array because ArrCell is composed of vectors and matrices of different sizes, i.e. size of [new] is different, or could be different, than [1]

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Fletcher Garrison
编辑：Fletcher Garrison 2021-2-3
You can also use:
Arrcell = {1,2,3,4,5};
new = magic(5);
Arrcell = horzcat(new,Arrcell);

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