RESHAPE Reshape An Array

Section: Array Generation and Manipulations

Usage

Reshapes an array from one size to another. Two seperate syntaxes are possible. The first syntax specifies the array dimensions as a sequence of scalar dimensions: 
   y = reshape(x,d1,d2,...,dn).

The resulting array has the given dimensions, and is filled with the contents of x. The type of y is the same as x. The second syntax specifies the array dimensions as a vector, where each element in the vector specifies a dimension length: 

   y = reshape(x,[d1,d2,...,dn]).

This syntax is more convenient for calling reshape using a variable for the argument. The reshape function requires that the length of x equal the product of the di values. Note that arrays are stored in column format, which means that elements in x are transferred to the new array y starting with the first column first element, then proceeding to the last element of the first column, then the first element of the second column, etc.

Example

Here are several examples of the use of reshape applied to various arrays. The first example reshapes a row vector into a matrix. 
--> a = uint8(1:6)

a = 
 1 2 3 4 5 6 

--> reshape(a,2,3)

ans = 
 1 3 5 
 2 4 6

The second example reshapes a longer row vector into a volume with two planes. 

--> a = uint8(1:12)

a = 
  1  2  3  4  5  6  7  8  9 10 11 12 

--> reshape(a,[2,3,2])

ans = 

(:,:,1) = 
  1  3  5 
  2  4  6 

(:,:,2) = 
  7  9 11 
  8 10 12

The third example reshapes a matrix into another matrix. 

--> a = [1,6,7;3,4,2]

a = 
 1 6 7 
 3 4 2 

--> reshape(a,3,2)

ans = 
 1 4 
 3 7 
 6 2