How to pull an item and save it into an array/matrix from a Cell that is composed of a Struct

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nas illmatic 2015-10-17

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回答： nas illmatic 2015-10-18

I have a myVar which is a 1x27 Cell, where each Cell is a Struct. Within the Struct is a Field called myPullItem that I want to grab. However 'pull' with a '(i)' afterwards to increment the array produces an error; when I remove the (i), it only provides me the last cell's Struct myPullItem

 for i=1:length(myVar)
   pull(i) = myVar{i}.myStruct.myPullItem
 end

Error: In an assignment A(:) = B, the number of elements in A and B must be the same.

My objective is to save each field. I am attempting to do this by incrementing through each cell of Structs and saving it.

What am I doing wrong? Thx.

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Answer 1

nas illmatic 2015-10-18

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I think I got it. Apparently you need to define 'pull' first. So, you need to define it as

pull=cell(1)

And then it works.

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Answer 2

James Tursa 2015-10-18

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编辑：James Tursa 2015-10-18

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pull(i) is likely a scalar, while myVar{i}.myStruct.myPullItem is likely not a scalar. You are trying to stuff multiple values into a scalar, hence the error.

What is myVar{i}.myStruct.myPullItem? Once we know the size we can offer suggestions (e.g., using another cell array, or perhaps an nD array, etc). E.g., something like this:

pull{i} = myVar{i}.myStruct.myPullItem;

or maybe this:

pull(:,:,i) = myVar{i}.myStruct.myPullItem;

Again, can't tell for sure what will work for you until we know what the rhs is.