mat2cell

Convert array to cell array whose cells contain subarrays

Syntax

C = mat2cell(A,dim1Dist,...,dimNDist)

C = mat2cell(A,rowDist)

Description

C = mat2cell(A,dim1Dist,...,dimNDist) divides array A into smaller arrays and returns them in cell array C. The vectors dim1Dist,...dimNDist specify how to divide the rows, the columns, and (when applicable) the higher dimensions of A. The smaller arrays in C can have different sizes. A can have any data type.

C = mat2cell(A,rowDist) divides array A into an n-by-1 cell array C, where n equals the number of elements in rowDist.

Examples

Divide Array and Return Subarrays in Cell Array

Create a 5-by-4 numeric array.

A = reshape(1:20,5,4)'

A = 4×5

     1     2     3     4     5
     6     7     8     9    10
    11    12    13    14    15
    16    17    18    19    20

Divide A into two 2-by-3 and two 2-by-2 subarrays. Return the subarrays in a cell array.

C = mat2cell(A,[2 2],[3 2])

C=2×2 cell array
    {2x3 double}    {2x2 double}
    {2x3 double}    {2x2 double}

Display the subarrays in C using the celldisp function.

celldisp(C)

 
C{1,1} =
 
     1     2     3
     6     7     8

 
 
C{2,1} =
 
    11    12    13
    16    17    18

 
 
C{1,2} =
 
     4     5
     9    10

 
 
C{2,2} =
 
    14    15
    19    20

 

Divide Array by Rows

Create an array.

A = reshape(1:20,5,4)'

A = 4×5

     1     2     3     4     5
     6     7     8     9    10
    11    12    13    14    15
    16    17    18    19    20

Divide the rows of A so that the cell array contains two subarrays. Since the first element of rowDist is 1, the first cell of C contains the first row of A. The second element of rowDist is 3, so the next cell of C contains the next three rows of A. The sum of the elements of rowDist equals the number of rows of A.

rowDist = [1 3];
C = mat2cell(A,rowDist)

C=2×1 cell array
    {[1 2 3 4 5]}
    {3x5 double }

Display the subarrays.

celldisp(C)

 
C{1} =
 
     1     2     3     4     5

 
 
C{2} =
 
     6     7     8     9    10
    11    12    13    14    15
    16    17    18    19    20

 

Input Arguments

A — Input array

array

Input array.

dim1Dist,...,dimNDist — Distributions of input array elements

numeric vectors

Vectors describing the distributions of input array elements along each dimension, specified as numeric vectors.

For example, if A is a 60-by-50 array, then you can specify this argument as [10 20 30],[25 25] to divide A as shown in the code and figure. C is a cell array that contains the six subarrays split out of A.

C = mat2cell(A,[10 20 30],[25 25])

For the Kth dimension of A, specify the elements of the corresponding vector dimKDist so that sum(dimKDist) equals the size of the Kth dimension.

If the Kth dimension of A has a size of zero, then specify the corresponding vector dimKDist as the empty array, [], as shown in the code.

A = rand(3,0,4);
C = mat2cell(A,[1 2],[],[2 1 1]);

rowDist — Distribution by rows

numeric vector

Vector describing the distribution by rows of the input array, specified as a numeric vector. When you do not specify how to divide A along any other dimension, the mat2cell function returns an n-by-1 cell array C, where n equals the number of elements in rowDist.

Each element of rowDist specifies the number of rows in the subarray that is in the corresponding cell of C. The sum of the elements of rowDist must equal the number of rows of A.