MATLAB Function Reference    

Array dimensions



d = size(X) returns the sizes of each dimension of array X in a vector d with ndims(X) elements.

[m,n] = size(X) returns the size of matrix X in separate variables m and n.

m = size(X,dim) returns the size of the dimension of X specified by scalar dim.

[d1,d2,d3,...,dn] = size(X) returns the sizes of the first n dimensions of array X in separate variables.

If the number of output arguments n does not equal ndims(X), then for:

n > ndims(X)
size returns ones in the "extra" variables, i.e., outputs ndims(X)+1 through n.
n < ndims(X)
dn contains the product of the sizes of the remaining dimensions of X, i.e., dimensions n+1 through ndims(X).


Example 1. The size of the second dimension of rand(2,3,4) is 3.

Here the size is output as a single vector.

Here the size of each dimension is assigned to a separate variable.

Example 2. If X = ones(3,4,5), then

But when the number of output variables is less than ndims(X):

The "extra" dimensions are collapsed into a single product.

If n > ndims(X), the "extra" variables all represent singleton dimensions:

See Also

exist, length, whos

   sinh size (serial)