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.
C{1,2}
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.
C{1,1}(1,2)
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.
C{2,1}{1,2}
ans = 'two'
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.
C{2,2}.Field2(5,1)
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'