MATLAB Function Reference 
Syntax
Description
d = size(X)
returns the sizes of each dimension of array X
in a vector d
with ndims(X)
elements. If X
is a scalar, which MATLAB regards as a 1by1 array, size(X)
returns the vector [1 1]
.
[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),
for n
> 1, returns the sizes of the dimensions of the array X
in the variables d1,d2,d3,...,dn, provided the number of output arguments n
equals ndims(X)
. If n
does not equal ndims(X)
, the following exceptions hold:
Note
For a Java array, size returns the length of the Java array as the number of rows. The number of columns is always 1. For a Java array of arrays, the result describes only the top level array.

Examples
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
sinh  slice 
© 19942005 The MathWorks, Inc.