Documentation

Access Data in Cell Array

This example shows how to read and write data to and from a cell array.

Create a 2-by-3 cell array of text and numeric data.

C = {'one', 'two', 'three';
1, 2, 3}
C=2×3 cell
{'one'}    {'two'}    {'three'}
{[  1]}    {[  2]}    {[    3]}

There are two ways to refer to the elements of a cell array. Enclose indices in smooth parentheses, (), to refer to sets of cells--for example, to define a subset of the array. Enclose indices in curly braces, {}, to refer to the text, numbers, or other data within individual cells.

Cell Indexing with Smooth Parentheses, ()

Cell array indices in smooth parentheses refer to sets of cells. For example, to create a 2-by-2 cell array that is a subset of C, use smooth parentheses.

upperLeft = C(1:2,1:2)
upperLeft=2×2 cell
{'one'}    {'two'}
{[  1]}    {[  2]}

Update sets of cells by replacing them with the same number of cells. For example, replace cells in the first row of C with an equivalent-sized (1-by-3) cell array.

C(1,1:3) = {'first','second','third'}
C=2×3 cell
{'first'}    {'second'}    {'third'}
{[    1]}    {[     2]}    {[    3]}

If cells in your array contain numeric data, you can convert the cells to a numeric array using the cell2mat function.

numericCells = C(2,1:3)
numericCells=1×3 cell
{}    {}    {}

numericVector = cell2mat(numericCells)
numericVector = 1×3

1     2     3

numericCells is a 1-by-3 cell array, but numericVector is a 1-by-3 array of type double.

Content Indexing with Curly Braces, {}

Access the contents of cells--the numbers, text, or other data within the cells--by indexing with curly braces. For example, to access the contents of the last cell of C, use curly braces.

last = C{2,3}
last = 3

last is a numeric variable of type double, because the cell contains a double value.

Similarly, you can index with curly braces to replace the contents of a cell.

C{2,3} = 300
C=2×3 cell
{'first'}    {'second'}    {'third'}
{[    1]}    {[     2]}    {[  300]}

You can access the contents of multiple cells by indexing with curly braces. MATLAB® returns the contents of the cells as a comma-separated list. Because each cell can contain a different type of data, you cannot assign this list to a single variable. However, you can assign the list to the same number of variables as cells. MATLAB® assigns to the variables in column order.

Assign contents of four cells of C to four variables.

[r1c1, r2c1, r1c2, r2c2] = C{1:2,1:2}
r1c1 =
'first'
r2c1 = 1
r1c2 =
'second'
r2c2 = 2

If each cell contains the same type of data, you can create a single variable by applying the array concatenation operator, [], to the comma-separated list.

Concatenate the contents of the second row into a numeric array.

nums = [C{2,:}]
nums = 1×3

1     2   300