CODEWITHSUNDEEP
matlab
user2646609
user2646609

Reputation: 1

How to create an empty array in a matrix

How to create an empty array in matlab that accepts elements from a matrix when you do not know the no.of elements it is going to contain ?

Upvotes: 0

Views: 2752

Answers (2)

Pacific Stickler
Pacific Stickler

Reputation: 1097

You can use the empty matrix/vector notation, [], and Matlab will set up a placeholder for it. 

x = []

Now if you want to append a scalar, say num, to it, you cannot index it because it is empty.

However, you can either:

  1. Use array concatenation to concatenate itself with another scalar:

    x = [x num]

  2. Use the end+1 notation, to address the first available location:

    x(end+1) = num

Both of the above two notations also work when you want to append a row or a column vector to an existing row vector or column vectors. But when you are concatenating vectors/matrices, remember to be consistent with the dimensions.

Upvotes: 0

Shaked
Shaked

Reputation: 495

Use the [] operator. Example:

x = [];

If you wanna be specific in the type of the empty matrix, use the empty property. Examples:

emptyDoubleMatrix = double.empty; % Same as emptyDoubleMatrix = [];
emptySingleMatrix = single.empty;
emptyUnsignedInt8Matrix = uint8.empty;

This works for empty matrices of classes as well. Example:

emptyFunctionHandleMatrix = function_handle.empty;

Upvotes: 1

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