Main Content

Multilevel Indexing to Access Parts of Cells

This example shows techniques for accessing data in arrays stored within cells of cell arrays.

Create a sample cell array.

myNum = [1, 2, 3];
myCell = {'one', 'two'};
myStruct.Field1 = ones(3);
myStruct.Field2 = 5*ones(5);

C = {myNum, 100*myNum;
     myCell, myStruct}
C=2×2 cell array
    {[ 1 2 3]}    {[100 200 300]}
    {1x2 cell}    {1x1 struct   }

Access the complete contents of a particular cell using curly braces, {}. For example, return a numeric vector from the cell that contains it.

ans = 1×3

   100   200   300

Access part of the contents of a cell by appending indices, using syntax that matches the data type of the contents.

Enclose numeric indices in smooth parentheses. For example, C{1,1} returns the 1-by-3 numeric vector, [1 2 3]. Access the second element of that vector using smooth parentheses.

ans = 2

Enclose cell array indices in curly braces. For example, C{2,1} returns the cell array, {'one','two'}. Access the contents of the second cell within that cell array using curly braces.

ans = 

Refer to fields of a struct array with dot notation, and index into the array as described for numeric and cell arrays. For example, C{2,2} returns a structure array, where Field2 contains a 5-by-5 numeric array of fives. Access the element in the fifth row and first column of that field using dot notation and smooth parentheses.

ans = 5

You can nest any number of cell and structure arrays. For example, add nested cells and structures to C.

C{2,1}{2,2} = {pi, eps};
C{2,2}.Field3 = struct('NestedField1', rand(3), ...
                       'NestedField2', magic(4), ...
                       'NestedField3', {{'text'; 'more text'}} );

Access parts of the new data using curly braces, smooth parentheses, or dot notation.

copy_pi = C{2,1}{2,2}{1,1}
copy_pi = 3.1416
part_magic = C{2,2}.Field3.NestedField2(1:2,1:2)
part_magic = 2×2

    16     2
     5    11

nested_cell = C{2,2}.Field3.NestedField3{2,1}
nested_cell = 
'more text'

Related Topics